







Problème de géométrie 
20050429 

Christian pose la question : C un cercle de centre I et de rayon 3 cm.
SORT est un carré inscrit dans le cercle C
M est un point quelconque de C Calculer la somme des carrés des distances de M aux sommets du carré (MS2 + MO2 +MR2 + MT2)
Cette somme dépendelle de la position de M sur le cercle ? Claude Tardif lui répond. 





An equilateral triangle inscribed in a circle 
20170915 

sumit pose la question : what is the area (in sq. unit) of an equilateral triangle inscribed in the circle x^2+y^24x6y23=0. Penny Nom lui répond. 





A rope formed in a semicircle 
20170829 

Janna pose la question : How do I find the total length of a piece of rope formed in a semicircle that has a diameter of 8 inches? Penny Nom lui répond. 





Two circles 
20170813 

Ladines pose la question : Find the equation of the circle passing through points of intersections of circles x²+y²=4y and x²+y²=2x and the center is on line y=2 Penny Nom lui répond. 





A rectangle and a circle 
20170812 

Ramzan pose la question : a diagram shows the shape of rectangular framework with length (2x+20)cm and with (y+10)cm . The outline is made of wire . If a circle with diameter 56 cm is to be made from the wire and the area of the rectangle is 420 square centimeter ,find the possible lengths and width of the rectangle Penny Nom lui répond. 





The equation of a circle 
20170703 

Chen pose la question : Find the center radius and equation of a circle in standard form given the following conditions:
1. Tangent to 3x+2y=0 at the point (0,0) and passing through (1,1) and (6,0) Penny Nom lui répond. 





A polygon inscribed in a circle 
20170527 

Levan pose la question : This was the closest to what I am trying to solve.
http://mathcentral.uregina.ca/QQ/database/QQ.09.06/s/dj1.html
So in the answer linked, we figure out what is "c".
But what if we know "c" and want to find out "n" based on specific "r=1".
It might be simple math, but I have not had any relationship with math for 20 years now
but this question puzzles me for a reason. Penny Nom lui répond. 





A trapezoid inscribed in a circle 
20170517 

Kameron pose la question : I have been given a challenge problem that states that Diameter AB is drawn in a circle if 10 inch. Chords AC and BD are drawn so that each is of length 12inch and ACDB is a trapezoid. Find the height, in inches, of the trapezoid Penny Nom lui répond. 





Forming a cone from a circle 
20170415 

Tasha pose la question : A sector of a circle subtends an angle of 216 degrees at the centre, If this sector is used to form a cone of vertical height ,8cm, calculate the base radius of the cone Penny Nom lui répond. 





A circle inscribed in a 30690 triangle 
20170407 

Kameron pose la question : i have been given a problem with a 306090 triangle and a circle inscribed with a radius of 2 and was told to find the perimeter of the triangle Penny Nom lui répond. 





The volume of a slab 
20170121 

Russell pose la question : Working with a segment of a circle. The O.D. is 3.440" the length of the chord is 3.130 I need information on the volume of the largest area. I would like to know (in thousands of an inch) how tall would the largest area need to be to equal .1143 cubic inches If you need more info I can send it Thanks in advance p lui répond. 





A circle inscribed in an isosceles triangle 
20170114 

Sal pose la question : There is a right isosceles triangle. Inscribed inside of it, is the largest possible circle.
Ho do you find the value of the radius?
I want to find out a way of only using the rules/laws of geometry, or is that not possible. Penny Nom lui répond. 





Two concentric circles 
20161221 

shrestha pose la question : Two concentric circles have radii of 14 cm and 7 cm respectively. Find the area of space between them. Penny Nom lui répond. 





The area and radius of a circle 
20161219 

india pose la question : How do you find the radius of a circle if only the area is given to you? Penny Nom lui répond. 





Two tangent circles 
20161127 

mikee pose la question : find the equation of a circle tangent to the circle x2+y2=4
and with the center at (0,5) Penny Nom lui répond. 





A circle inscribed in an equilateral triangle 
20161127 

jo pose la question : what is the radius of the inscribed circle of an equilateral triangle with altitude 12 units? Penny Nom lui répond. 





A square inside a circle inside a square 
20161113 

Jeff pose la question : Greetings,
I came across a question from a textbook from years ago. I've been trying to solve it, but am not sure if my approach is correct.
There are 2 squares (1 inner, 1 outer) & 1 circle.
The inner square is the largest square that will fit inside the circle. It has an area of 1 unit.
The circle is the biggest that will fit in the outer square.
What is the area of the outer square? Penny Nom lui répond. 





Three circles 
20161030 

yolani pose la question : two equal circles with centre A (1;1)and B (4;5)touch a third circle with centre P as shown in the diagram. If P ,A and B Lie on a straight line find the coordinates of P Penny Nom lui répond. 





A circle formed from bending a wire 
20161016 

Deszaree pose la question : The same piece of a wire is bent to form a circle
calculate:
a, the radius of the circle
b, the area of the circle Penny Nom lui répond. 





The equation of a circle 
20160930 

Trent pose la question : write the equation of circle B with center B(2,3) that passes through (1,2) Penny Nom lui répond. 





The area of a circle 
20160812 

sandeep pose la question : if circumference of a circle is πd what is the area? Penny Nom lui répond. 





A triangle inscribed in a circle 
20160422 

Olyana pose la question : I am struggling with this question! Help!
So, there is a circle. In the circle, there is an equilateral triangle inscribed.
Each side of the triangle is 20. There is no other info given, other than
the triangle is inscribed in the circle and the sides of the triangle are 20.
I am supposed to find the radius of the circle! Please help! Penny Nom lui répond. 





A sector of a circle 
20160421 

mustafa pose la question : In a sector of a circle, the arc length is equal to half the perimeter of a sector.find the area of a sector in terms of r Penny Nom lui répond. 





The area of a circle and a square 
20160410 

Richard pose la question : I cannot understand why if you have a perimeter say of 4 units as the circumference of
a circle then you reshape it into a square you lose very approximately some 20% of its
volume but the perimeter length stays the same.
Can you please explain this to me as to why the volume decreases. Penny Nom lui répond. 





A square based box and a cylinder 
20160326 

rajpal pose la question : i m trying to calculate an area required to hold 4.4 mln cubic metres of volume.
I used square and I get below result
A box shape that has dimensions 1500 meters (1.5km) by 1500 meters (1.5km) by 2 meters depth has a volume of:
= 4,500,000 cubic meters (4.5 mln cubic meters)
but when I use a cylinder shape, i get below result
A cylindrical shape that has a radius of 850 meters and a depth of 2 meters has a volume of:
= 4,539,600 cubic meters (4.54 mln cubic meters approx)
why is it that the cylinder, though of same depth holds more volume than a square?
kindly clarify. Penny Nom lui répond. 





An isosceles triangle inscribed in a circle 
20160325 

NIHAL pose la question : A isosceles triangle is inscribed in a circle having sides 20cm,20cm,30cm. find the radius of circle Penny Nom lui répond. 





A circle and a chord 
20160310 

Mujtaba pose la question : The distance of a chord of length 16 cm, from the centre of the circle of diameter 20 cm Penny Nom lui répond. 





Can you construct a regular 21gon? 
20160308 

Peter pose la question : hi, i know that if i use a compass to draw a circle, i can use the same setting to mark 6 intervals along the circle circumference, how would i go about marking out 21 equally spaced points around the circumference?
if there an online calculator i can us, or some other interesting trick?
tia
peter Robert Dawson lui répond. 





A circle is inscribed in a hexagon 
20151228 

Lalitesh pose la question : A circle is inscribed in a regular hexagon ABCDEF
Prove that AB+CD+EF=BC+DE+FA Penny Nom lui répond. 





A diameter of a circle 
20151227 

sahil pose la question : Find the equation of diameter of circle x2 +y26x +2y8 which passes through the origin. Penny Nom lui répond. 





Drawing an arc 
20151204 

hassan pose la question : how to draw a curve long 1m with an angle of 22.5? Penny Nom lui répond. 





A tangent line to a circle 
20150903 

Jamie pose la question : Use the Greek method to find an equation of the tangent line to the circle
x^2+y^24x+6y+4=0 at the points (3,2square root 23. Penny Nom lui répond. 





The diameter and circumference of a circle 
20150901 

Tracey pose la question : Hello,
I own a custom workroom, I am figuring out fabric quantities or an estimate. When
at the job site, I forgot to measure the diameter of the semi circle shape that I have to
make a cushion for!!!
If the circumference of the semi circle is 165" what would the diameter be, maybe half
this measurement????
I appreciate any help...I basically need the width from left to right to see if I can fit
the cushion on one width of fabric that is 52" wide! Penny Nom lui répond. 





An equilateral triangle inscribed in a circle 
20150611 

Casey pose la question : I have an equilateral triangle inscribed in a circle  this triangle
has been bisected to give me 2 right triangles. I know the length
of the line bisecting the equilateral triangle is 36 inches. How do
I figure out the circumference of the circle and the length of the
sides of the equilateral triangle? Penny Nom lui répond. 





A pentagon inscribed in a circle 
20150530 

Victoria pose la question : find the area of a regular pentagon inscribed in a circle with radius 3 units Penny Nom lui répond. 





Two concentric circles 
20150528 

Shannan pose la question : Two concentric circles have radii of 24cm and 26cm. What is the length of the chord that is tangent to the inner circle? Include a sketch Penny Nom lui répond. 





The perimeter of a quarter circle 
20150521 

Bethany pose la question : The perimeter of a quarter circle is 3.57. What is the quarter circle's radius? Penny Nom lui répond. 





A triangle inscribed in a circle 
20150507 

R2D2 pose la question : A triangle is inscribed in a circle of radius 10. If two angles are 70 degrees and 50 degrees find the length of the side opposite the third angle? Chris Fisher lui répond. 





A circle is tangent to the yaxis 
20150506 

Elynna pose la question : What does it mean when a circle is tangent to the yaxis?
Thanks, Penny Nom lui répond. 





Locating the center of a circle that forms an arc 
20150423 

Ken pose la question :
Find the Cartesian coordinates of the center of an arc with the given location of the beginning and end points and radius length. Not the midpoint of the circumference but the actual point that the arc
is drawn around.
I know their are two answers depending on the direction of the arc. Unless we assume that all arcs are drawn counter clock wise.
Thanks
Ken
Harley Weston lui répond. 





Two concentric circles 
20150421 

Juniper pose la question : Two concentric circles have radii of 4 cm and 8 cm. A segment is drawn so that it is tangent to the smaller circle and a chord of the larger circle. How long is the segment? Penny Nom lui répond. 





A circle inscribed in a square 
20150419 

michael pose la question : A circle is drawn in a square PQRS. If the total area of the shaded portion of the square is 42 cm square, calculate the radius of the circle Penny Nom lui répond. 





The area of a circle given the circumference 
20150412 

F pose la question : How do you find the area of a circumference of 6?
Thanks. Penny Nom lui répond. 





An 8 pointed star inscribed in a circle 
20150410 

Kermit pose la question : How do you find the area of the star that is formed by two squares and surrounded by a circle. The only given information is that the radius of the circle is 10. Penny Nom lui répond. 





The perimeter of a quarter circle 
20150410 

Riley pose la question : How do you find the perimeter of a quarter circle when the radius is 56? Penny Nom lui répond. 





The area of the ring between two concentric circles 
20150408 

Conner pose la question : The area of the ring between two concentric circles is 25pi/2 square inches. The length of a chord of the larger circle tangent to the smaller circle is? Robert Dawson lui répond. 





A circle graph 
20150406 

Davis pose la question : i don't know how to answer this question. please help!
a survey about student government shows the following results
110 like the program
120 think the program is unnecessary
210 plan on running for student government next year
if this information is put in a circle graph,what is the central angle for the students who like the program? Penny Nom lui répond. 





An isosceles triangle inscribed in a circle 
20150323 

Rachel pose la question : Triangle ABC is an isosceles triangle inscribed in circle O. If each leg of the triangle is 13cm and the altitude to the base of triangle ABC is 5cm, find the radius of the circle. Penny Nom lui répond. 





Two parallel tangents to a circle 
20150305 

Samantha pose la question : The equation of a circle is x^2+y^2=25. Determine
the equation of the parallel tangent lines to this
circle, for which the slope is 4/3. Penny Nom lui répond. 





Two concentric circles 
20150225 

Manasi pose la question : The area between 2 concentric circles is 6 times the smaller circle. Radius of small circle is 7 cm. Find the difference in the circumference of the bigger circle ad the smaller circle? Penny Nom lui répond. 





A circle and a chord 
20150207 

Dakota pose la question : If the diameter of a circle is 48 cm, find the shortest distance from a chord of length 34 cm to the center of the circle Penny Nom lui répond. 





The center and radius of a circle 
20150206 

ariana pose la question : I need to find the center and the radius of this circle. I don't know how to put 9/2
than square it into a fraction.
x^2 + 2x + y^2 +9y=5 Penny Nom lui répond. 





Two concentric circles 
20150125 

nazneen pose la question : select the correct answer from the given four options
given are two concentric circles. radii of outer circle & inner circle are r1 & r2 respectively.
the areas of inner circle & shaded ring are equal. the radii r1 & r2 are related by?
1. r1 = r2
2. r1 = r2*square root 2
3. r1 = r2*square root 3
4. r1 = 2r2 Penny Nom lui répond. 





The perimeter of a quarter circle 
20141226 

Maisy pose la question : This is the question that I got for a math worksheet.
The radius of a quarter circle is 5 miles. What is the quarter circle's perimeter?
Use 3.14 for pi. Penny Nom lui répond. 





A tangent to a circle 
20141222 

azman pose la question : Find the equation of the tangent line to the circle x^2+y^2=9 at the point P (2, square root of 5). Penny Nom lui répond. 





A circle through 3 points 
20141204 

priyanka pose la question : Find the equation of a circle passing through the origin and intercept on axes are a and b. Penny Nom lui répond. 





An irregular convex octagon 
20141113 

james pose la question : I have an irregular convex octagon, alternating between 4 large edges, say 'a' mm long and 4 small edges, say 'b' mm long, is there a formula available so that I can work out the minimum size sit a circle with a radius of 34.25mm inside it thank you Chris Fisher lui répond. 





The area of a circle in terms of the circumference 
20141104 

Sarah pose la question : How do you find the area of a circle if you already have the circumference?
There was one answer to this question already but it didn't make sense to
me, because they rounded up pi which you can't do so the answer is
incorrect. thanks Penny Nom lui répond. 





The region between two concentric circles 
20141027 

Ray pose la question : two circles, concentric; Given the length of chord of outer circle that is tangent to inner circle. what are the areas of both? how to calculate? Penny Nom lui répond. 





How does pir^2 = 1/4pid^2? 
20141014 

al pose la question : Hi I cant work out the algebra. How does pir^2 = 1/4pid^2 Thanx Penny Nom lui répond. 





Trig functions and the unit circle 
20141002 

Jake pose la question : I was wondering what conclusions can be drawn about the trigonometric functions and how they work about the circle. Can you also please give me an explanation for it? Thank you. Penny Nom lui répond. 





Two chords in a circle 
20140913 

Carlos pose la question : Find the length of the radius of a circle in which a
chord of length 6 units is twice as far from the
center as a chord of length 12 units Penny Nom lui répond. 





Cutting a round cake so that it doesn't dry out 
20140826 

James pose la question : I'm wondering if there's a simple way to calculate the area between two parallel chords of a circle equidistant from its diameter, or if I have the area, to find the distance between the two chords.
Here's my "problem". You may have heard of the way of cutting a round cake so that it doesn't dry out  make two parallel cuts (chords) the length of the cake, take the middle piece, then push the two pieces together.
So I know the area of a 12" cake, and I want say, exactly an eighth of the cake. How wide do I cut the centre piece?
Now to get even more difficult, the next day I want another eighth from the centre. How wide do I cut the next pieces, and so on...?
Thanks,
James Harley Weston lui répond. 





The equation of a circle 
20140814 

jennifer pose la question : hi there My name is Jennifer and residing in Denmark. I am a student and I wrote to you because i am having trouble in finding out the equation for the circle using
(xa)^2 + (yb)^2 =3D r^2.The diameter of this circle is d=3D 44,514 cm.
I have attached a drawing of my problem..thanks Penny Nom lui répond. 





Covering a 12 inch by 12 inch square hole 
20140702 

Patricia pose la question : I am putting in a new bathroom fan. I am wondering if a new light with a 15 inch diameter will cover the existing square hole which is 12 by 12 inches? If the existing hole is 11 1/2 by 11 1/2 inches?
Also, if the 15 inch diameter does not cover the 12 by 12 hole, what size diameter would?
Thank you. Penny Nom lui répond. 





The area of a circle of circumference 32.69 meters 
20140611 

coco pose la question : Find the area of a circle with a circumference of 32.69 meters. Penny Nom lui répond. 





A circle a square and a rectngle 
20140512 

mazhar pose la question : suppose the length and breadth of the rectangle are 5 cm and 10 cm respectively and M is a point along the corner of the circle. what is the radius of the circle?(diagram is given..but i didn't mention it..actually the diagram looks like a circle inscribed in a square and the right bottom corner one rectangle will be given ,it is touches to circle at a point M that I've already mentioned and the dimensions of that rectangle also I've mentioned) please help me out.. Penny Nom lui répond. 





A circle is divided into three sectors 
20140417 

atolagbe pose la question : the area of a circle is 154cm square. it is divided into three sectors such that two of the sectors are equal in size and the third sector is three times the size of the other two put together. calculate the perimeter of the third sector. take pi=22/7? Penny Nom lui répond. 





Two circles that touch each other externally 
20140408 

Ameya pose la question : Two circles of radii a and b (a > b) touch each other externally. ST is a common tangent touching the circles at S and T respectively, then ST^2 is equal to Chris Fisher lui répond. 





Cutting a hexagon from a disk 
20140405 

Paul pose la question : I am a machinist and sometimes need to make a hex from
round material.
If I know the distance of the flat sides opposite one another
of my hex, how can I calculate the size of material I need to turn
to give me the right diameter to finish the part with six sides? Penny Nom lui répond. 





A circle inscribed in a right triangle 
20140316 

akshaya pose la question : A circle with centre O and radius r is inscribed in a right angled triangle ABC. If AB=5 cm, BC=12 cm and < B=90*, then find the value of r. Penny Nom lui répond. 





Two overlapping arcs in a square 
20140315 

Jean pose la question : I have a square with side 4 cm. There are two overlapping arcs going from vertex to diagonal vertex. The other two vertices are the center of the arcs, which are shaded. How do I find the area of the shaded arcs? The overlapping arcs when shaded resemble a long thin football
Thank you for your help. Penny Nom and Walter Whiteley lui répond. 





A circle which is tangent to two perpendicular lines 
20140309 

MJ pose la question : I'm a College Student taking up Bachelor of Secondary Education on Math Subject.
And I'm struggling for my research about Circles. I done solving the said topic particularly on this question:
"What are the possible equations of a circle being tangent to a pair of perpendicular lines, having the origin as the Point of Intersection and the C (h, k), where h, k ∈ℤ"
But I can't get what would be the process that I must do in order to jive to my idea/goal for that problem.
Please check my idea that the numerical coefficients of the equation is equal to the radius of the circle.
Thanks in advance! :) Penny Nom lui répond. 





The equation of a circle 
20140307 

Balraj pose la question : I have to draw a circle x^2+y^2 =8x . please tell me how to understand these coordinates ? please elaborate , on how to understand these types of equations. Penny Nom lui répond. 





A circle graph 
20140306 

Caitlyn pose la question : I need to find the measure of the central angle that represents the amount of time spent on each activity.
My question includes a circle graph with the following: Sleep 31%, Other 15%, Entertainment 18%, Errands 7%,
Work 20%, and Food 9%. Penny Nom lui répond. 





A circle through three points 
20140222 

Mohammad pose la question : Find the equation of circle passing through the origin and the points (a,b) and (b,a).
Find the length of chords that it cuts off from the axes. Chris Fisher lui répond. 





A rectangle inscribed in a circle 
20140110 

Marian pose la question : A 16 cm by 12 cm rectangle is inscribed in a circle. Find the radius of the circle. Penny Nom lui répond. 





An equilateral triangle inscribed in a circle 
20140106 

Anonymous pose la question : An equilateral triangle with sides 6 inches is inscribed in a circle. What is the diameter of the circle? Penny Nom lui répond. 





A circle insubscribed in an isosceles trapezoid 
20131208 

Bob pose la question : A circle is insubscribed in an isosceles trapezoid, with
parallel lengths of 8cm and 18cm.
What is the lengths of sloping edges and why? Robert Dawson lui répond. 





2 concentric circles 
20131127 

Dimaris pose la question : The radius of the outer circle of 2 concentric circles is x. An
equilateral triangle inscribed in the outer circle also circumscribes the
inner circle. What is the radius of the inner circle in terms of x? Penny Nom lui répond. 





A string wrapped around three circles 
20131019 

Jim pose la question : A recent puzzle ' find the length of a string around 3 touching
1 meter diameter circles ' gave this answer : the string
touches 120° (or pi/3 meters) of each circle. Then
3(1+pi/3) = 3+pi meters is the required length. I do not see how
it was determined that the string touches 120° or pi/3 meters?
Please explain . Thankyou , Jim Penny Nom lui répond. 





A square inscribed in a circle 
20131014 

Jenn pose la question : Hello! I am about to buy a 7'9" round rug, but I want to have it cut down into a square. What's the largest square I can obtain from this? Thank you! Penny Nom lui répond. 





Four tangent circles 
20131009 

Nilesh pose la question : Four circular cardboard pieces, each of radius 7cm are placed in such a way that each piece touches two other pieces. How to find the area of the space enclosed by the four pieces?
Please let me know. Robert Dawson lui répond. 





The area of a semicircle 
20130728 

Lucy pose la question : Find the area of the the figure described: a semicircle with arc length 3 pi. Penny Nom lui répond. 





Four circles 
20130529 

varsha pose la question : four circular cardboard pieces each of radius 7cm are placed in such a way that each piece touches two other pieces. find the area enclosed by the four pieces. Penny Nom lui répond. 





Two overlapping circles 
20130522 

Alexandra pose la question : There are two overlapping circles. The two nonoverlapping regions have areas A and B.
As the area of overlap changes, the values of A and B also change.
Prove that no matter how big and small the overlap is, the difference between
A and B is always the same. Penny Nom lui répond. 





A circle and a chord 
20130514 

yashvardhan pose la question : A circle which radius 13cm. Find the length of the chord which is 5 cm away from center Penny Nom lui répond. 





A triangle and an incircle 
20130509 

Max pose la question : On my Geometry Test about tangent, chord, and secant lengths, my teacher gave an extremely difficult problem.
It was a Circle inscribed in a Triangle with all triangle sides being tangents and lengths were given. My class was told to find the length of each segment of the line.
The points on each line were the vertexes of the triangle, and the point where the line hits the circle.
Please explain how someone could do this. Chris Fisher lui répond. 





A circle, a chord and an arc 
20130416 

Tim pose la question : Morning,
I was told the chord is 3000mm and the depth of chord is 300mm, I can
find the radius,(1500 squared + 300 Squared) Divided by (300 + 300)
but don't know how to calculate the length of the circle defined by the chord.
Regards
Tim
Penny Nom lui répond. 





The tangent to a circle at a point on the circle 
20130222 

Andrew pose la question : What is the equation of the line tangent to the circle with equation x^2+y^2=25 at the point (4,3) Penny Nom lui répond. 





The equation of a circle 
20130211 

mhd pose la question : Complete the equation of the circle centered at(0,4) with radius 3 Penny Nom lui répond. 





An equilateral triangle inscribed in a circle 
20130117 

Nicole pose la question : How do you find the shaded region of a circle if an unshaded equilateral triangle in inscribed in it. The only other things I know about the problem are that the side lengths of the equilateral triangle are 14 inches. Penny Nom lui répond. 





Milling round stock to square stock 
20121217 

Bryan pose la question : Question from Bryan:
I want to know what the smallest diameter round is that will make a 31/4" square? Is there a formula for that? I am milling round stock into square.
Thank you. Harley Weston lui répond. 





A circle inscribed in a triangle 
20121128 

Angie pose la question : Circle O is inscribed in triangle ABC. Angle A = 50 and angle B = 60. Find arc XY in dgrees Penny Nom lui répond. 





A path around a pond 
20121116 

bailey pose la question : hi there,
A circular pond is surrounded by a path 1 metre wide.
The area of the path is 1/4 of the area of the pond.
Find the radius of the pond.
Thanks Penny Nom lui répond. 





Two congruent circles in a rectangle 
20121020 

Alexander pose la question : Have you ever solved a problem, in which you have a rectangle, from which you need to cut the largest two circles of equivalent diameter? I bisected a rectangle diagonally, but the circles, while tangent to two of the sides, are not tangent to eachother. Can you devise a method for two equivalent circles, that are tangent to two sides, are also to eachother?
Take for example a piece of paper, Each if the two largest circles has a diameter that is greater than the distance to the midpoint of the diagonal bisector of the rectangle. Chris Fisher lui répond. 





The degree measure of the central arc of a circle 
20121017 

Crystal pose la question : On a circle with radius of 12 cm is an arc of length 20 cm. What is the degree measure of the central angle used to make this arc? Penny Nom lui répond. 





Two circle problems 
20121005 

shahad pose la question : question 1
find an equation for the circle through the point (0,0) and (6,0) that a tangent to the line y=1
question 2
find an equation for the circle through the point (0,0) and (17,7) whose center lies on the line 12x5y=0 Penny Nom lui répond. 





Four tangent circles 
20121004 

renu pose la question : inside of a circle K of radius length measure R,three circular discs A,Band C each of radius r are placed so that each touches the other two and K . express R in terms of r. in the space between K, A and B , another circular disc D is placed which just touches K, A and B. if the radius is s, show that (6+root3)s=(2+root3)r Penny Nom lui répond. 





An equilateral triangle and a regular hexagon in a circle 
20120911 

Heidemarie pose la question : The vertices of an equilateral triangle with side length of 10 sqrt 3 cm lie on a circle. Find the side length of the regular hexagon whose vertices lie on the same circle. Penny Nom lui répond. 





The distance between overlapping circles 
20120726 

Jeff pose la question : I have two circles of different size that overlap one another:
Circle #1 has an area(A) of 731,475, so I can calculate its radius as 482.6.
Circle #2 has an area(A) of 502,517, so I can calculate its radius as 400.
If I know that the area where they overlap is 179,271, how can I calculate the distance between the midpoints of these two circles? Chris Fisher lui répond. 





A regular hexagon inscribed in a circle 
20120725 

jim pose la question : A regular hexagon with an area of 24√3 is inscribed in a circle. What is the area of the circle? Penny Nom lui répond. 





A reel of cotton thread 
20120605 

Grace pose la question : 91 meters of cotton goes round the cotton reel. About how many times does the cotton go round the reel?
Give your answer to the nearest ten.
(The Diameter of the cylinder is 3cm) Penny Nom lui répond. 





The area of a semicircle 
20120528 

Rebecca pose la question : how do you find the area of a semi circle and then how do you add the area of a semi circle and the area of a rectangle? Penny Nom lui répond. 





A 10 inch circle using 2x4s 
20120519 

Ralph pose la question : I want to form a 10" circle with 4"high pieces of 2 x4's. If each 2x4 piece sit next to each other,What degree would I have to cut
each side of the 2x4's, and how many would I need to form a 10 inch circle. I know there is a formula for this out there somewhere. Harley Weston lui répond. 





A circle inscribed in a triangle inscribed in a circle 
20120426 

Maty pose la question : How do i find the area of a triangle inscribed a circle while another smaller circle is circumscribed by the same triangle and the radius is 8. Chris Fisher lui répond. 





A common chord to two circles 
20120422 

Nicole pose la question : What is a common chord between two circles and how is it found in the problem: Two circles intersect and have a common chord, the radii of the circles are 13 and 15, the distance between the circle's centers is 14, find the common chord. Penny Nom lui répond. 





The sarsen circle 
20120421 

Firdous pose la question : I found the circumference but after what to do I am not getting the question is.The diameter of the sarsen circle is 33 meters,since there were originally 30 sarsen stones located on the circumference, how far apart wold the centres of the stones have been?Round to the nearest tenth of a meter. Penny Nom lui répond. 





A tangent line to a circle 
20120414 

Novelyn pose la question : find an equation of the line tangent to a circle with equation x^2+y^2+6x8y27=0 at the point P(1,2) Penny Nom lui répond. 





A circle drawn around a equilateral triangle 
20120401 

BIMAL pose la question : what is the diameter of a circle drawn around a equilateral triangle of size 6 cm Penny Nom lui répond. 





Two overlapping circles 
20120321 

Monty pose la question : If you have a 3.75" radius circle overlapping a 5" radius circle with their centers 3" apart what would be the area of the nonoverlapped portion of the small circle? Penny Nom lui répond. 





Circles 
20120311 

Deniz pose la question : Two circles are externally tangent and the lengths of their diameters are 4 and 6. Find the length of the segment joining the centers of the circles. Penny Nom lui répond. 





A circle inscribed in a quarter circle 
20120220 

sonam pose la question : ABC is a quarter circle and a circle is inscribed in it and if AB=1cm than find radius of a small circle. Penny Nom lui répond. 





A circle and a chord 
20120211 

Sophia pose la question : The diagram shows a circle with a chord that is 10cm long. The middle of the chord is 12cm from the centre of the circle. Calculate the radius.
Chord length is 10cm.
The distance from the centre to chord is 12 cm. Penny Nom lui répond. 





Two circles 
20120208 

crisfe pose la question : find the point where the common cord of the circles x2+y2=25, x2+y212x6y+35=0 process there line centers. what point they intercepts? Penny Nom lui répond. 





Great circle course 
20120125 

Hervé pose la question : On the earth, the mathematical formula giving the distance
between two points, and the initial course for a boat on the great circle
is well known.
I need to find the inverse formula, ie knowing an initial position on earth,
and the initial course of the boat, and the distance to run on the great circle,
the formula gives the final position (longitude and latitude). Robert Dawson lui répond. 





A fountain 
20120124 

kris pose la question : A fountain has a radius of 14 meters to its outer edge. Their is an inner ring in the center of the fountain, where a statue of Sir Isaac Newton stands, that does not contain water. The inner ring has a diameter that is 6m less than the diameter of the outer ring of the fountain. What is the circumference of the inner ring? What is the area that is covered by water in the fountain? Penny Nom lui répond. 





Four pizzas 
20120123 

kris pose la question : a pizza company wishes to put 4 medium pizzas in a box to sell as a party pack. The box they want to use the square and has dimensions of 60cm by 60cm. They need you to help them calculate the dimensions of the pizza that will fit in the box. Calculate the following: area, radius, diameter, circumference Penny Nom lui répond. 





A circle inscribed in a regular octagon 
20120116 

Eric pose la question : I have a circle inscribed in a regular octagon. How do I determine the length of one side of the octagon if I know the radius of the circle (2.75 inches) ? p lui répond. 





The radius of a circle 
20120112 

Janie pose la question : Find the radius of a circle knowing that a chord of 24.6 inches has a corresponding arc of 70°. Penny Nom lui répond. 





An equilateral triangle and some circles 
20120110 

tushar pose la question : draw an equilateral triangle with side 6cm.draw 3circles with radii 3cm on each angular point of triangle.draw common tangent on each of two circles Penny Nom lui répond. 





Two shapes 
20120106 

muhammad pose la question : Question from muhammad, a student:
a boy has two pieces of wire each 99cm long .he bends them into the shapes shown below.calculate the radius of each figure,giving each answer to two decimal places.figures are one is semicircle and other on is half of the semicircle. Harley Weston lui répond. 





The circumference and area of a circle 
20111213 

Mable pose la question : A circle that going 70mi across using 22/7 I need the area,radius, and the circumference
and how to set up the steps can you help? Penny Nom lui répond. 





Two circles 
20111204 

Luke pose la question : Two fixed circles intersect at A and B.
P is a variable point on one circle.
PA and PB when produced meet the other circle at M and N respectively.
Prove that MN is of constant length.
Thanks!
p.s. I also sent the question with a figure via email. Chris Fisher lui répond. 





The perimeter of a quarter circle 
20111110 

sierra pose la question : how do you figure the perimeter of a quarter circle that has a radius of 12 Penny Nom lui répond. 





The area of a circle 
20111017 

Winney pose la question : If the diameter of a semicircle is 3 feet what is the area. Penny Nom lui répond. 





One central circle and three tangent circles 
20111016 

Margaret pose la question : You have one central circle and three or more circles tangent to the outside of the circle of varying radii. You know the x,y coordinates of the centers of the other circles. If you now remove that central circle (and pretend you never knew where it was), can you calculate its center in x,y coordinates? Chris Fisher lui répond. 





Two great circles 
20111006 

Jean pose la question : "Two great circles lying in planes that are perpendicular to each
other are drawn on a wooden sphere of radius "a". Part of the sphere
is then shaved off in such a way that each cross section of the
remaining solid that is perpendicular to the common diameter of the
two great circles is a square whose vertices lie on these circles.
Find the volume of this solid."
I don't understand the geometry of the problem.
Can you please explain the problem and if possible draw a diagram for me
? Chris Fisher lui répond. 





A trapezoid inscribed in a circle 
20111002 

Greg pose la question : A trapezoid is inscribed within a circle.
The two interior angles who share the longest side are 70 and 80.
The arc whose chord is the longest side has a length of 120.
Find the other two interior angles of the trapezoid, and the other three arc lengths. Chris Fisher lui répond. 





Decartes' circle theorem 
20110907 

Joseph pose la question : Given 3 circles of diameters 50, 55, and 60 units,
Place them externally tangent.
What is the diameter of the outer circumscribing circle,
tangent to all 3 circles? I can attach a pdf if this description is not clear.
Not urgent, this has nothing to do with current assignments,
just wondering if I have developed the best methods? Chris Fisher lui répond. 





Three tangent circles 
20110821 

maribie pose la question : three discs are tangent externally distances between their centers are 23cm, 15cm, and 20cm. find their radii.t Penny Nom lui répond. 





Three tangent circles 
20110819 

hanniel pose la question : two coin are tangent to a third coin internally and are tangent to each other
externally. The distance between their centers are 14 mm, 17mm, and 5mm.
find their radii Penny Nom lui répond. 





A 3 foot circle using 1/2" cord 
20110804 

Cindy pose la question : To make a 3 foot circle using 1/2" cord  how many lineal feet of cord
do I need? Robert Dawson lui répond. 





A point on a circle 
20110802 

George pose la question : I know the center location (x,y) of the circle, I know the radius of the circle, I know the location (X,Y) of one point on the circle, and I know the angle (in degrees not radians) between the known point location (X,Y) and an unknown point location (let's call it (A,B) for reference). What formula(s) can I use to find out the coordinate position of (A,B)? Chris Fisher lui répond. 





A regular hexagon inscribed in a circle 
20110718 

Courtney pose la question : If ABCDEF is a regular hexagon inscribed in a circle of
radius r, prove that the length of each side of the hexagon
equals r. Penny Nom lui répond. 





A rectangle is inscribed in a circle 
20110717 

Alexea pose la question : A rectangle is inscribed in a circle of diameter 15in. Express the perimeter as a function of the width x. Penny Nom lui répond. 





concentric circles 
20110706 

maribiie pose la question : two circles are concentric. the tangent to the inner circle forms a chord of 12cm in the larger circle. find the area of the "ring" between the two circles? Penny Nom lui répond. 





A circle inscribed in a triangle 
20110507 

Aishwarya pose la question : The angles of a triangle are 50, 60, and 70 degrees, and a circle is touches the sides at A, B, C. Calculate the angles of the triangle ABC. Penny Nom lui répond. 





Three tangent circles 
20110501 

mark pose la question : Three circles of radii 24 cm, 32 cm, and 42 cm are externally tangent to each
other (each is tangent to the other two). Draw a diagram and using the Law of
Cosines find the largest angle of the triangle formed by joining their centres. Penny Nom lui répond. 





cos(x) = 1/(square root of 2) 
20110427 

Shelby pose la question : Find exact value of x for 1 <(or equal to) x < 2pi
a) cos(x) = 1/(square root of 2) Penny Nom lui répond. 





The length of a chord 
20110425 

G pose la question : A 120 degree central angle intercepts a circle at the points A and B. The radius of the circle is 10 cm. Find the length of chord AB. Penny Nom lui répond. 





The degree measure of an arc in a circle 
20110408 

Deb pose la question : How do I find the degree measure of an arc in a circle with the Length of 14 and the radius of 70? Penny Nom lui répond. 





A circle in a square in a circle in a square 
20110329 

George pose la question : A circle within a square which is inside
a larger circle which is also within a square.
(a circle in a square inside a circle in a square)
Equation of the smaller circle is: x ^ 2 x y ^ 2 = 25.
What are the dimensions of the larger square?
Been 40 years, trying to help my son. Penny Nom lui répond. 





A family of circles 
20110301 

steffi pose la question : Find the equation of the family of the circle passing through the the point of intersection of x^2+ y^2 4x28=0 and x^2 +y^2 4x20+52=0; the member tangent to x=7. Penny Nom lui répond. 





A circle is inscribed inside an isosceles trapezoid 
20110225 

priyam pose la question : a circle is inscribed inside an isosceles trapezoid (with parallel sides
of length 18 cm and 32 cm) touching all its four sides.
find the diameter of the circle.
thanks for help!! Penny Nom lui répond. 





The equation of a circle 
20110214 

Cristela pose la question : find the equation and all the information in General Form and Standard Form of the Circle that will passed trough the point (2,3) (6,1) (4,3) Stephen La Rocque lui répond. 





Two tangent circles 
20110209 

xhesika(jessica) pose la question : Two circles of radius 10 are tangent to each other.A tangent is drawn
from the centre of one of the circles to the second circle.To the nearest
integer find the area of the shaded region. Penny Nom lui répond. 





A tangent to a circle 
20110206 

debz pose la question : what is the formulae of the tangent to a circle.... our teacher gave us a lot of homework.. and she ask us to find the formulae by ourselves.. Penny Nom lui répond. 





The perimeter of a semicircle 
20110129 

Keith pose la question : I have the perimeter of a semi circle of 37 but how do I calculate the diameter from this.
This is all the information I have. Penny Nom lui répond. 





Semicircles and the Pythagorean Theorem 
20110109 

Jas pose la question : Okay well, in math we are learning about the pythagorean theorem and we have to do a math journal on the question:
****Can you replace the squares (that are put on the sides of a right triangle) with semicircles and still get the same answer??
I do not understand because i tried doing an example and comparing it with a normal way of doing it and I didnt get the same answer! Penny Nom lui répond. 





A sector of a circle 
20110107 

Alice pose la question : the radius of a circle is 7cm the angle of the sector is 68 how do you find the Penny Nom lui répond. 





A circle inside a square 
20101231 

Jenn pose la question : A circle of a diameter of 2 is drawn inside a square of 4. The circle's center is at the center of the square. To the nearest tenth, what is the perimeter of the area of the square, not including the circle inside. Penny Nom lui répond. 





The perimeter of a quarter circle 
20101215 

kim pose la question : how do you figure the perimeter of a quarter circle that has a radius of 7 inches? I would like to have the explanation of how you figure it out. Thank you Penny Nom lui répond. 





Two chords in a circle 
20101202 

girma pose la question : one chord of a circle is 8cm long and it's distance from the center is 4cm long.what will be the length of another chord, of the same circle ,which is 2cm from the center Penny Nom lui répond. 





A sector of a circle 
20101129 

Mel pose la question : Find the area of a sector of a circle that has a central angle of 13pi/18 and a radius of 12cm. Round answer to nearest 10th degree Penny Nom lui répond. 





The perimeter of a semicircle 
20101111 

gayathri pose la question : the area of semicircle is 1925sq.cm find perimeter Stephen La Rocque lui répond. 





The equation of a circle 
20101020 

Silvan pose la question : Hi, I just want to find the x,y values for the circumference of a circle...
Lets take a clock having its centre at (0,0) in a graph.
I just want to know how to find the (x,y) coordinates for the curved path or the surface of the circle..
Is there any formula to directly align the curved path or the circumference of the circle in a graph for a known radius of a circle..
I feel it will be useful for me to draw a clock in a graph... :) Penny Nom lui répond. 





Limiting Cases in Geometry 
20100922 

Niki pose la question : Consider a rectangle inscribed in a circle with a radius or R. What are the possible perimeters for the rectangle? Stephen La Rocque lui répond. 





Find the point of contact of the circles 
20100920 

Sandra pose la question : If the center of circle A = (1,3) and the radius of it is √20,
the center of circle B = (5,9) and the radius of it is √80.
Find the point of contact of the circles A and B. Janice Cotcher lui répond. 





The circle centered at (2,4) with radius 3 
20100918 

lupe pose la question : Consider the circle centered at (2,4) with radius 3. Write the equation
of this circle sketch its graph, and find the exact coordinates of its intercepts.
xintercept
yintercept using the quadratic equation? Penny Nom lui répond. 





Two overlapping circles 
20100804 

Husen pose la question : two circles of radius 5 cm intersect each other .the distance between their centers is 5root 2.find the area of the portion common to the two circles Penny Nom lui répond. 





The diameter of a circle 
20100624 

John pose la question : Piece of wire 72cm in length bent to make semicircle and diameter.Find
length of diameter.Answer given 28cm.How is this arrived at?Looked at
circumference in various ways but failed to understand how 28 cm was
arrived at.Thanks for the help. Robert Dawson lui répond. 





The equation of a circle 
20100623 

Michelle pose la question : Write and equation for the circle with a center, (0,0) and a diameter of 12 Penny Nom lui répond. 





3 equidistant points on a circle 
20100621 

Brian pose la question : We have to line up 3 pins on a lifting bridle to be 120 degrees apart from each other to connect into a lifting assembly.
I know pi*d. I know straight lines connecting these points to each other will result in an equilateral triangle.
How does one find these points without using a protractor? There must be a formula (formulae) to work this out mathematically.
r = 10.5 inches
pi*d = 65.9736
3 segments( arcs) = 21.9912 which is the distance along the circumference that the points are from each other. Penny Nom lui répond. 





The area of a circle 
20100612 

grier pose la question : please,
what is the area of a semicircle with arc length 3pi? Penny Nom lui répond. 





Four circles in a square 
20100604 

Daniela pose la question : four circles are drawn in a square such that the circles are tangent to each other as shown. find the area of the shaded region. It the goes on to show a diagram with a square and four circles drawn in it. The length of a side of the square is 24. Please help me! Penny Nom lui répond. 





A square inscribed in a circle 
20100525 

Middle pose la question : what is the perimeter of a square inscribed in a circle of radius 5.0 inches? Penny Nom lui répond. 





The circumference of a circle 
20100512 

Morgan pose la question : find the circumference of a circle with radius 8.
im having trouble i just don't understand. thanks for your help i really do appricate it. Penny Nom lui répond. 





The equation of a circle 
20100504 

crystal pose la question : find the standard form of the circle with center (2,3) and tangent to the line y=1 Penny Nom lui répond. 





The diameter of a circle 
20100430 

Jimmy pose la question : If I have a straight line with a known length and decide to make a circle out of this know length how would I calculate what the diameter of the circle would be Penny Nom lui répond. 





A circle inscribed in a square inscribed in a circle 
20100428 

jouniella pose la question : A square is inscribe to the first circle, then another circle is inscribe to the square. Find the ratio of the 2 circles. Penny Nom lui répond. 





The area of semi circle 
20100416 

sagir pose la question : how to find the area of semi circle? Penny Nom lui répond. 





A tangent line to a circle 
20100415 

Rhonda pose la question : The Greek method for finding the equation of the tangent line to a circle used the fact that at any point on a circle the line containing the reauis and the tangent line are perpendicular. Use this method to find an equation of the tangent line to the circle x^2+y^2=9 at the point (1,2 square root of 2). Penny Nom lui répond. 





Two overlapping circles 
20100412 

Scott pose la question : There are two circles, big circle with radius R and small one with radius r. They intersect and overlap in such a way that the common area formed is 1/2 pi r^2 (half the area of the small circle). The Question is: suppose we have known the radius r of the small circle, and the distance between the two circle centers, what should the radius R of the large circle be? Chris Fisher lui répond. 





An isosceles trapezoid is inscribed in a circle 
20100406 

Abby pose la question : An isosceles trapezoid whose bases have lengths 12 and 16 is inscribed in a circle of radius 10. The center of the circle lies in the interior of the trapezoid. Find the area of the trapezoid Penny Nom lui répond. 





A max min problem 
20100406 

Terry pose la question : The vertex of a right circular cone and the circular edge of its base lie on the surface of a sphere with a radius of 2m. Find the dimensions of the cone of maximum volume that can be inscribed in the sphere. Harley Weston lui répond. 





A regular hexagon and an equilateral triangle in a circle 
20100405 

Beth pose la question : A regular hexagon and an equilateral triangle are both inscribed in the same circle so that the hexagon and the triangle share three vertices. The radius of the circle is 10cm. What is the difference between the area of the hexagon and the area of the triangle? Chris Fisher lui répond. 





A rectangle inscribed in a circle 
20100324 

sadiq pose la question : here is the question,
in my mathematics book there is equation of the area of the rectangle
inscribed in a circle having equation x^2+y^2=a^2
and the area of rectangle is 4xy=4x(a^2b^2)^1/2
i don't know what is b but a is surely the radius
(i want the derivation for the area of rectangle). Harley Weston lui répond. 





Water in a culvert 
20100318 

Chip pose la question : Hello,
I have a problem to which I know there must be an analytical solution  but as it has been 50 years since I studied math I can't remember quite how to do it!! I have a 12" round culvert in my yard that runs water all year. I would like to be able to calculate the flow through the culvert by measuring the depth of water flowing through and measuring the speed of the current. I can measure the depth and the speed, but I forget how to calculate the cross section of the flow. If you could help I would greatly appreciate it.
Thank you Penny Nom lui répond. 





Two overlapping circles 
20100307 

Hayden pose la question : I have two circles of equal size. The radiuses of the circles are 30ft. The two circles are positioned 40ft apart and I need to find the area where they overlap. Harley Weston and Tyler Wood lui répond. 





A related rates problem 
20100303 

Amanda pose la question : A circle is inscribed in a square. The circumference of the circle is increasing at a rate of 6 inches per second. As the circle expands, the square expands to maintain the tangency. Determine the rate at which the area of the region between the circle and square is changing at the moment when the cricle has an area of 25(pi) square inches. Penny Nom lui répond. 





The equation of a circle 
20100218 

AHMED pose la question : find the equation to the circle with centre at the point (1,1) and touching the straight line 5x+12y=7. Penny Nom lui répond. 





The perimeter of a semicircle 
20100204 

Sarah pose la question : The perimeter of a semicircle is doubled when the radius is increased by 7. Find the radius of the semicircle. Tyler Wood lui répond. 





Bending a wire to form shapes 
20100204 

Geraldine pose la question : a wire bent into the shape of a square encloses an area of 25cm squared. then the same wire is cut and bent into two identical circles. what is the radius of one of the circles round to the nearest hundred Penny Nom lui répond. 





A sector of a circle 
20100204 

trisha pose la question : Given a circle with a radius of 6 inches. Find the area of the sector that is formed by an arc of 36 degrees. Round your answer to the nearest tenth of an inch. Penny Nom lui répond. 





A circular photo in an octagonal frame 
20100113 

Mike pose la question : I have a circle photo 18 and one quarter inches round. I want to cut frame for it in a octagon shape. What would the angle and the length of cut be?
Mike Robert Dawson lui répond. 





The area of a sector 
20100107 

angelkem pose la question : how do you get the area of the circle, the sector, the shaded sector, non shaded sector and its total area if the diameter is 20 cm and each area of the circle is 45 degrees? Penny Nom lui répond. 





A question from a boat builder 
20100101 

Grant pose la question : I am a boat builder, trying to lay out shape of side's elevation.
My question is, how do I define the length of a circle's radius, if I know the chord length
(20 ft) and the segment of the radius between the chord and the circle is known (7 inches)? Penny Nom lui répond. 





Chord length given the length & radius of an arc 
20091231 

Wayne pose la question : Given the length & radius of an arc, is there a formula that will accurately calculate the chord length?
I'm an architectural designer, and would need it explained in layman's terms. Thank you.
Wayne Penny Nom lui répond. 





A circle problem 
20091214 

Fawad pose la question : AP is a tangent at P to a circle centre O, where AP=6cm. The straight line AQC is such that QC= 9cm.
Find the length, in cm of AQ. Chris Fisher lui répond. 





A regular pentagon 
20091214 

Jamie pose la question : A regular pentagon is inscribed in a circle of radius 4.5 cm.
Determine its perimeter and area to one decimal place!
Thank YOU ! :) Penny Nom lui répond. 





An equilateral triangle is inscribed in a circle 
20091206 

anna pose la question : An equilateral triangle is inscribed in a circle of radius 6. Find x and the length of
one side of the equilateral triangle. The picture is a triangle where the corners touch the
sides of a circle and there is a line drawn down the middle of the triangle. A point labeled
D which is in the triangle but im pretty sure that its marking the radius of the circle.
From that point D is a line going from that point to the bottom left corner of the triangle.
So this line shall make another mini triangle. The bottom of the big triangle is then split
into 2 segments and the left segment is labeled x. Please help for I am stuck! Penny Nom lui répond. 





Two overlapping circles 
20091119 

Raraa pose la question : There are two identical circles . The edge of one circle is at the middle point of the other circle. There were overlapped . The area of the overlapped surface is 20000 square centimetres . How do I find the radius of the circle rounded to the nearest whole centimetre ? Penny Nom lui répond. 





A minute hand 
20091105 

Pardha pose la question : A minute hand of table clock is 3cms long. How far its tip move in 20 minutes Penny Nom lui répond. 





A path around a pond 
20091031 

adeniji pose la question : find the area of a concrete path 2m wide surrounding a circular pond 12m in diameter Penny Nom lui répond. 





A line and a circle 
20091019 

Renson pose la question : Determine whether the line x2y=0 cuts,touches or fail to meet the circle x^2+y^28x+6y15=0.If it touches or cuts ,find the coordinates of the point(s) of contact Harley Weston lui répond. 





The equation of a circle 
20091017 

Renson pose la question : A circle passes through (4,2) and (11,5) with center on the line 3y5x+41=0.Determine its equation in standard form. Penny Nom lui répond. 





Concentric circles 
20091014 

maddy pose la question : Find the exact area of the region bounded by two concentric circles with radii 10 inches and 6 inches. Penny Nom lui répond. 





Three circles 
20091002 

Brandon pose la question : There is a quarter circle with a radius of 1. along one eged of it,
there is a semicircl with a diameter of 1, and its center is on the
drawn line. there is another semicircle again with the center on the
other drawn line, and this one has an unknown diameter of X. both
circles are internally tangent, and are tangent to each other. Find X. Robert Dawson and Chris Fisher lui répond. 





Seven circles 
20090920 

Bobbi pose la question : try to put number 1 to 7 in seven circles (one in the middle, 3 on top, 3 below) so the numbers in each row of three circlesvertical, horizontal, and diagonal  add up to 12. Each number can be used only once. Stephen La Rocque lui répond. 





The equation of a circle 
20090830 

tagbo pose la question : find the eqn of circle passing through (1 1) and (1 4)and whose radiusis 5/2 Stephen La Rocque lui répond. 





Two circles 
20090803 

Karan pose la question : We are given 2 circles with radii 12cm and 3 cm. We have to find AB Penny Nom lui répond. 





Circular Measures 
20090724 

onyeka pose la question : find the equation of a circle with point [3,7][5,5] and wich center lies on the line x4y=1 Robert J. Dawson lui répond. 





A degreaser for a fish tank 
20090723 

charlie pose la question : I have a tank that is 10 feet in diameter that I want to put floating degreaser in.The rate for the degreaser is 1/2 gallon per square foot of surface water.How do I figure out how many gallons I need? Penny Nom lui répond. 





A tangent to a circle 
20090714 

Eric pose la question : Hi I am trying to complete a packet that has a list of questions to brush up on precalculus skills. The question asks "For the circle x^2 +y^2 + 6x  4y + 3 = 0 find : the equation of the tangent at (2,5). I have already found the equation for the circle and standard form and the center and radius. However, i do not know how to find the slope or yintercept of the tangent line. Please help. Thanks. Stephen La Rocque lui répond. 





Two chords 
20090711 

Sarah pose la question : Two parallel chords in the same circle have lengths of 30 cm and 48 cm. The circle has a radius of 25 cm. How far apart are the chords? Penny Nom lui répond. 





Arc length 
20090710 

farhad pose la question : hi
i need to measure length of arc by having only two measurements, first the length of the chord and
the height of the curve.
if i have a simple calculator that haven't sin cos tang (i want to calculate it in my mind) Stephen La Rocque lui répond. 





A circle and a chord 
20090710 

Paul pose la question : I have three known points. X1,Y1 = 0,0 X2,Y2 = 3,1 and X3,Y3 = 10,0. Given these three points, how do I find the height from the center of the 10' chord to the circle's circumference above? Stephen La Rocque and Harley Weston lui répond. 





Two circles on a dome 
20090701 

Beth pose la question : My question is related to a dome I would like to construct, for which I know the circumference of the base: 120ft.
I now need to figure out the diameters of two smaller circles, one at 20ft along the arc of the dome form the ground,
and the other at 30ft along the arc.
Assuming a true hemisphere, or 180 degrees total arc, how can I calculate these two circumferences?
Beth Stephen La Rocque lui répond. 





A maxmin problem 
20090420 

Charlene pose la question : A fixed circle lies in the plane. A triangle is drawn
inside the circle with all three vertices on the circle and two of the vertices at the
ends of a diameter. Where should the third vertex lie to maximize the perimeter
of the triangle? Penny Nom lui répond. 





A circle tangent to the Xaxis 
20090329 

Kiera pose la question : Find an equation of the circle that satisfies the stated conditions.
Center C(4,1), tangent to the xaxis Penny Nom lui répond. 





A rolling wheel 
20090329 

Jules pose la question : How far does a wheel of radius 2 feet roll along level ground in making
300 revolutions? Penny Nom lui répond. 





The diameter of a roll of plastic 
20090324 

truong pose la question : hi. i have trouble to calculate the diameter of the plastic roll. the sheet is 765 m long and 0.8 mm to wrap around the core 400 mm in dia. please help me with the formula to calculate the dia of plastic roll, thanks in advance Harley Weston lui répond. 





The radius of a circle 
20090322 

Justin pose la question : Find the radius of a circle with a circumference of 9.43cm. Penny Nom lui répond. 





A regular decagon is inscribed in a circle 
20090312 

Renata pose la question : A regular decagon is inscribed in a circle of diameter 36 feet. Approximate the perimeter and area of the decagon. Robert Dawson lui répond. 





A goat in a square paddock 
20090210 

lachlan pose la question : A farmer uses a rope to tether a goat to a pole at the corner of a square paddock. The length of one side of the square is 24m.
a) If the length of the rope is 12m,what % of the paddock can the goat reach? is the answer 19.62 %?
b) If the farmer wants the goat to be able to graze exactly half the area of the paddock, what length must the rope be? Penny Nom lui répond. 





A regular hexagon is inscribed in a circle. 
20090126 

Thejas pose la question : A regular hexagon is inscribed in a circle. If the perimeter of the hexagon is 42 inches, how many inches are in the circumference of the circle?
How do you express this in the terms of pi? Robert Dawson and Penny Nom lui répond. 





Two tangent circles 
20090123 

Murtaza pose la question : Two circles touch externally at T. A chord of the first circle XY is produced and touches the other at Z. The chord ZT of the second circle, when produced, cuts the first circle at W. Prove that angle XTW = angle YTZ. Robert Dawson and Chris Fisher lui répond. 





A cyclic quadrilateral 
20090123 

Murtaza pose la question : Line ATB touches a circle at T and TC is a diameter. AC and BC cut the circle at D and E respectively.Prove that the quadrilateral ADEB is cyclic. Robert Dawson and Chris Fisher lui répond. 





Two chords in a circle 
20090119 

azlaan pose la question : prove that line joining the midpoint of 2 equal chords substain equal angle with the chord? Robert Dawson lui répond. 





A wooden deck around a pool 
20090109 

lupio pose la question : a 20' pool is surrounded by a 3' wood deck, find the amount of material needed for the project Robert Dawson and Penny Nom lui répond. 





A chord 
20090101 

Deepa pose la question : Why in a circle,a chord is called as the longest diameter?
(A chord does not passes through the centre of the circle but a diameter passes through the centre) Penny Nom lui répond. 





Three circles inscribed in a circle 
20081218 

seema pose la question : three equal circles each of radius 1 cm are circumscribed by a larger circle.find the perimeter
of circumscribing circle? Robert Dawson lui répond. 





The centroid and circumcircle of a triangle 
20081209 

prateet pose la question : in an equilateral triangle prove that the centroid and centre of the circumcircle coincide
here i am not clear about the concept of centroid and circumcircle
i cant understand how AGis 2/3 AD.
please help in details about the topic mentioned. Harley Weston lui répond. 





Two tangent circles and common tangents 
20081201 

Alan pose la question : Radius of big circle 30cm, radius of small circle 10 cm. From the diagram, the radius from the tangent do not form a semicircle but at an angle. Find the perimeter of the band around both the circle. May need to use trigonometry to find reflex angle AOB, CMD and get the major arc length AB and minor arc length CD Penny lui répond. 





Two tangents to a circle 
20081126 

rogerson pose la question : The length of the tangent to a circle is 15 cm. If the angle between the two tangent lines to the circle is 28 degrees, what is the radius of the circle? Penny Nom lui répond. 





Four circles in a square 
20081119 

Anthony pose la question : I have a square where one side measures 10cm and within that square
There are four equal quarter circles. Each quarter circles starts in a
different corner of the square and I am trying to find area inside the
overlap on the quarter circles. Janice Cotcher, Chris Fisher and Penny Nom lui répond. 





A circle and a chord 
20081117 

Lydz pose la question : The circle has a radius of 8cm
The chord is 13cm long.
Find the distance from the centre of the circle, to the chord. Penny Nom lui répond. 





A circle and a chord 
20081113 

jane pose la question : the center of a circle is at (3,2) and its radius is 7. find the length of the chord, which is bisected at (3,1). Penny Nom lui répond. 





A circle tangent to a line and with its centre on another line 
20081101 

liza pose la question : Find the equation of the circle of radius squareroot 26 tangent to the line 5x+y=13 and having its center on the line 3x+y+7=0. Chris Fisher lui répond. 





The diameter of a circle 
20081101 

lupito pose la question : a circle has a 30`sector,33pi.find the diameter of the circle.How do I set the equation up. Victoria West lui répond. 





How far does the ball travel? 
20081101 

Betty pose la question : This is a question that is perplexing me. I tried to solve it with the Pythagorean Theorem but have not been able to get the right answer. A ball attached to the moving end of the 5meter arm of a pendulum. The pendulum swings through a 90 degree arc once. Approximately how far, in meters, does the ball travel? Victoria West lui répond. 





A canal with cross section a semicircle 
20081019 

Connor pose la question : a canal with cross section a semicircle is 10m deep at the centre.
Find an equation for the semicircle and use it to find the depth 4m
from the edge Penny Nom lui répond. 





Area of a semicircle 
20081006 

Benjamin pose la question : How do you find the area of a semicircle if the diameter is a variable. Penny Nom lui répond. 





How many parallel tangents may a circle have? 
20080929 

Manish pose la question : how many parallel tangents may a circle have? the text book shows two.but a circle can have infinite tangents.then why not parallel tangents coz
theoretically each tangent have a parallel tangnts then no. of parallel tangent a circle may have is equals to half of the infinity i.e. infinity.. Walter Whiteley lui répond. 





The area of an arched transom 
20080928 

Ivan pose la question : What is the formula for figuring out the square footage of arched transom windows & doors? Harley Weston lui répond. 





5 units from (1,2) and 5 units from yaxis 
20080926 

Shaun pose la question : Find the points (x,y) in the plane that are 5 units from (1,2) and 5 units from yaxis.
I am more interested in the approach, in general terms, than the numerical values. Penny Nom lui répond. 





The region between two circles 
20080924 

Carol pose la question : Good day!
Here is a picture of the problem that we need to solve. (I send the picture through email.)
A small circle is inside a larger circle, the only given in the problem is the chord of the larger circle tangent to the smaller circle which measures 16cm. The question is, what is the area of the shaded region?
Can you answer this question? Thanks! :) Harley Weston lui répond. 





Parallel Tangents 
20080924 

manish pose la question : how many parallel tangents may a circle have? the text book shows two.but a crcle can have infinite tangents. Janice Cotcher lui répond. 





The area of a garden 
20080920 

Hannah pose la question : How do you find the area of a semi circle when no measurement is given?
The question is find the area of the garden which is semi circular.
The measurements are 24m and 26m and the semi circle's height is 10m! Penny Nom lui répond. 





An exclusion zone around a triangle 
20080907 

Awrongo pose la question : A long time ago Mr Gibson found an island shaped as a triangle with three straight shores of length 3 km,4 km and 5 km. He declared an 'exclusion zone' around his island and forbade anyone to come within 1 km of his shore. What was the area of his exclusion zone? Stephen La Rocque and Penny Nom lui répond. 





A tangent to a circle 
20080906 

Jake pose la question : Find an equation of the line that is tangent to the circle x^2 + y^2 = 3 at the point (1,√2) Penny Nom lui répond. 





Half a circle 
20080904 

brandon pose la question : what are the area and perimeter and area of half a circle?? Penny Nom lui répond. 





The length of an arc 
20080904 

Angie pose la question : Segment PR is a diameter of circle S. If angle P =3D 25, find minor
arc QR.
This circle has an isosceles triangle in it, it is connected to the
diameter, Harley Weston lui répond. 





Largest Inscribed Rectangle 
20080903 

astrogirl pose la question : find the shape and area of the largest rectangle that can be inscribed in a circle of a diameter a=2 Janice Cotcher lui répond. 





A triangle and an inscribed circle 
20080901 

Nancy pose la question : I'm a computer programming student, and I'm supposed to figure out how to find the area of a circle inside a triangle if someone types in the length of each side of the triangle.
So, a user can type in any three numbers they want into the three "side length" boxes, and I have to find the area of the circle that would fit inside the triangle they create from those values.
So the circle can be any size, depending on the size and shape of the triangle the user creates. The circle has to touch all three sides of the triangle somewhere. Then, my program calculates the area of the triangle and thus the area of the circle. I just need to know how the circle would change depending on the length of each side of the triangle that the user puts in. Is there a way to find out how the circle's area is related to the triangle around it? Chris Fisher lui répond. 





Radii and Chords Create a NonRight Triangle 
20080822 

Beary pose la question : AOC is a diameter of circle O. Line AB is 12, and lines OA and OC (the radii) are 10. Find the length of line BO and chord BC. Janice Cotcher lui répond. 





Two tangent circles 
20080822 

Michele pose la question : A circle of radius 2 is externally tangent to a circle of radius 8,
How do you find the length of their common tangent. Penny Nom lui répond. 





Irregular polygon and Circle that Intersects All Sides 
20080820 

Xetro pose la question : Hi,
Suppose you have an irregular polygon(convex or concave) with n > 3 sides.
The question is  Find some circle that will cut(in limiting case  touch) all the sides of that polygon.
It doesnt matter how many times it cuts the side(1 or 2), it just have to cut or touch it.
How to find such a circle? or how to decide if such circle even exists?
What if those segments do not form a polygon but are some arbitrary segments ?
Really want to know how to do it................
Thanks a lot..
Regards,
Xetro Janice Cotcher lui répond. 





Subdividing a chord 
20080818 

austin pose la question : Here is my question. Imagine I have a circle of known radius 25 feet, and a
chord with a mid point height of 6 inches from a central point on the chord
to the circumference of the circle. I wish to divide this chord into a
number of equal divisions. How can I calculate the measurement of the
perpendicular line at each division of the chord to the circumference and at
a 90 degrees at each division Penny Nom lui répond. 





Arclength and sectorangle 
20080806 

Benson pose la question : If chord length, radius are given, How to find the sector angle and arclength Janice Cotcher lui répond. 





Area of triangle formed by three tangent circles 
20080731 

brian pose la question : Three circles with radii 3,4 and 5 touch each other. The circles are tangent to each other. What is the area of the triangle formed by the centers of the circles? Stephen La Rocque lui répond. 





Inscribed Rectangle 
20080730 

Felicia pose la question : A rectangle whose base is twice its altitude is inscribed in a circle whose radius is 5 mm.
Find the area of the rectangle. Penny Nom lui répond. 





An isosceles triangle inscribed in a circle 
20080715 

Anne pose la question : Here is the math problem quoted from book:
"An isosceles triangle is inscribed in a circle of radius R,
where R is a constant. Express the area within the circle but outside
the triangle as a function of h, where h denotes the height of the triangle." Penny Nom lui répond. 





The length of an arc 
20080714 

Chris pose la question : trying to find the length of an arc or segment of a circle when
the radius or circumference is unknown
take a circle, put a line across the circle label it A /B /C
A and C are the end points, B is the middle
line length is 86. From B to the side of circle is 16. Label that point D
need to find the length of A D C Penny Nom lui répond. 





A tangent line to a circle 
20080709 

Rita pose la question : The tangent to a circle may be defined as the line that intersects the circle in a single point, called the point of tangency. If the equation of the circle is x^2 + y^2 = r^2 and the equation of the tangent line is y = mx + b, show
r^2(1 + m^2) = b^2 Harley Weston lui répond. 





CIRCLES 
20080707 

daryl pose la question : Find the equation of the smaller circle that is tangent to the axes and the circle x(squared)+y(squared)=2x+2y1? Penny lui répond. 





Two triangles and a circle 
20080703 

Anita pose la question : An equilateral triangle with side of length 1 cm is inscribed in a circle. A second equilateral triangle is circumscribed about the circle with all sides tangent to the circle. Find the length of a side of the second triangle. Harley Weston lui répond. 





A fivesided coin 
20080629 

carla pose la question : A new fivesided coin is to be made in the shape of figure 8.6
The point A on the circumference of the coin is the centre of arc CD, which has a radius of 2cm
Similarly B is the centre of arc DE, and so on.
Find the area of one face of the coin. Harley Weston lui répond. 





A circle inscribed in a square acre 
20080619 

Scott pose la question : Q'm trying to find out the sq footage of the corners of an acre. If an acre is 43,560 sq and if I have this right the surface area of the circumference is 1040 ft. what is the combined square footage of the 4 corners? Or the percentage the original acre? Harley Weston lui répond. 





A space camera circles the Earth 
20080616 

Rita pose la question : A space camera circles the Earth at a height of h miles above the surface. Suppose that d distance, IN MILES, on the surface of the Earth can be seen from the camera.
(a) Find an equation that relates the central angle theta to the height h.
(b) Find an equation that relates the observable distance d and theta.
(c) Find an equation that relates d and h.
(d) If d is to be 3500 miles, how high must the camera orbit above Earth?
(e) If the camera orbits at a height of 400 miles, what distance d on the surface can be seen? Penny Nom lui répond. 





If the arc is 75mm, what is the radius? 
20080612 

malcolm pose la question : If the are is 75mm, what is the radius? Janice Cotcher and Harley Weston lui répond. 





Two circles 
20080610 

cey pose la question : the diameter of the larger circle is 20cm, and the smaller 10cm. what is the shaded area?? Janice Cotcher lui répond. 





An ellipse and circle with the same area 
20080609 

Michael pose la question : The area of the ellipse if equal to the area of a circle with radius=40 ft.
Find the values of a and b using appropriate algebraic techniques, not basic math computations.
A=pi ab and satisfy the constraint a+b=100???? Penny Nom lui répond. 





Three mutually tangent circles 
20080604 

Jacob pose la question : If three circles are mutually tangent, does that mean that the two tangent lines are perpendicular? Chris Fisher lui répond. 





How many bricks I can place around a 26inch circle? 
20080522 

Jon pose la question : I want to know how many bricks I can place around a 26inch circle? There must be a formula other than trial and error. The length of the bricks is 6inches. [How many 6inch tangents can be in a 26inch circle?
Thank you very much.
Jon Harley Weston lui répond. 





A triangle inscribed in a semicircle 
20080519 

Larissa pose la question : Find the area of the shaded region outside of a triangle inscribed (meaning the all three points of the triangle are on the circle ) in a half circle of diameter 10 inches, if one side of the triangle is the diameter and the other side is 8 inches long. (A triangle that is inscribed in a triangle is a right triangle by definition.) Penny Nom lui répond. 





The wedges in a circle graph 
20080518 

Libby pose la question : I don't understand how to do this word problem:
The cafeteria workers distributed a survey to the student body asking students to pick 1 from a list of 5 choices for their favorite lunch. The circle graph below gives the results of the survey for the students who responded. What is the measure, in degrees, of the central angle for each choice?
And there is a pie chart that has food choices with these percentages: 25%, 20%, 15%, 10%, and 30% Leeanne Boehm and Penny Nom lui répond. 





The length of an arc 
20080512 

patricia pose la question : Find the length of the arc on a circle of radius r = 16 inches intercepted by a central angle [theta] = 60 degrees Penny Nom lui répond. 





The area of a sector of a circle 
20080510 

lupio pose la question : a problem asks for the area of a sector in a circle,no central angle,in circle is given only 5cm radius, three answers 1809035
can't find a way to start.Help Harley Weston lui répond. 





The distance from the chord to the centre 
20080504 

sle pose la question : What is the method for figuring this type of question out?
in a circle whose radius is 25, a chord has a length of 40. find the distance of this chord from the center of the circle Penny Nom lui répond. 





The diameter of a circle 
20080428 

Mary pose la question : What is the diameter of a circle if the area is 132.7 square meters? I have tried the formula C=2 times pi radius and came up up 21.1. I also tried C = pi times d and came up with 42.26. The answer in the book says 13. How did they get this answer? Thank you for your help. Penny Nom lui répond. 





A rectangle inscribed in a circle 
20080427 

sridhar pose la question : A rectangle with perimeter 28 cm inscribed in a circle of radius 5 cm
find the area ? Penny Nom lui répond. 





A circle inscribed in a triangle 
20080426 

Amar pose la question : I have been given a circle inscribed in a triangle and have been told to prove that the ratio of the perimeter of the triangle to the circumference of the circle is the same as the ratio of the area of the triangle to the area of the circle. How would this be done? Stephen La Rocque and Walter Whiteley lui répond. 





Two overlapping circles 
20080426 

Michelle pose la question : Two overlapping circles O and Q have the common chord AB (vertical line between the overlapping circles). If AB is 6 and circle O has a radius of length 4 (horizontal line going through the overlapping circles and touching the side of the circle) and circle Q has a radius of length 6, how long is OQ. Penny Nom and Walter Whiteley lui répond. 





The radius of a circle 
20080425 

kathy pose la question : How do you find the radius of a circle if the area is 803.84 and using 3.14 for pi. Penny Nom lui répond. 





Two intersecting circles 
20080417 

Muhammad pose la question : Hi, how can we find the perimeter and area of the region common to two intersecting circles of radii 6 cm and 4 cm with centers 7 cm apart. Harley Weston lui répond. 





A tangent to two circles 
20080413 

erson pose la question : find the length of the tangent segment AB to two circles whose radii are a and b respectively, when the circles touch each other.
the illustration looks like this...hope you'll understand...
there are 2 circles  one is big one is small. they touch each other. and there is this irregular 4 sided polygon that connects them...there is a line that connects them from their center point and another from the tip of the circles...and that's it...i cannot explain very well
please bear with me Stephen La Rocque lui répond. 





A tangent to a circle 
20080413 

rogerson pose la question : Line t from point P is tangent to circle O at T, the point of tangency. Find the length of PT when the radius of the circle is 5cm and the distance between points P and O is 8cm. Stephen La Rocque lui répond. 





Finding the radius when only given chord length 
20080403 

Lorraine pose la question : There are two chords in a circle, an 8 inch chord and a 10 inch chord. The 8 inch chord
is twice the distance from the center as the 10 inch chord. What is the radius? Stephen La Rocque lui répond. 





The area of a circle 
20080403 

Norm pose la question : how to compute the square footage of a circle Penny Nom lui répond. 





Circles and semicircles 
20080323 

sally pose la question : Hi i am sally ,
i need to know what is the formula of :
Find perimeter and area of a semicircle ?
Find the area of a circle whose circumference ? Penny Nom lui répond. 





Angles subtended by the same arc 
20080323 

Reid pose la question : Prove that two inscribed angles subtended by the same arc are equal. Stephen La Rocque lui répond. 





The radius of a circle 
20080322 

danny pose la question : waht is the radius of a circle, if the circumference is 800? Penny Nom lui répond. 





A pentagon inscribed in a circle 
20080319 

Elaine pose la question : My question as written on my homework is: Given a pentagon inscribed in a circle of radius r, determine a) the angle between any two sides of the pentagaon b) the perimeter of the pentagaon c) the area of the pentagon. I know this kind of counts as three questions, so if you can only answer one, that's okay. Any help will be much appreciated. Thanks! Stephen La Rocque lui répond. 





Any regular polygon inscribed in a circle 
20080317 

lindsay pose la question : how do find the perimeter of a regular octagon inscribed in a circle with a radius of 5 units Stephen La Rocque lui répond. 





A circle and a square 
20080312 

mae pose la question : what are the formulas on getting the area of the square outside an inscribed circular region? Penny Nom lui répond. 





The centre and radius of a circle 
20080312 

Ryan pose la question : hello and thank you for such a wonderful service.
This problem I think needs to be checked could you take a gander at it and tell me if i get it correct thanks
find the center and the radius of this circle x^2+y^2=8x2y+15=0
I cam up with center 2, 1/2 and a radius of 11 3/4 Harley Weston lui répond. 





A common chord to two circles 
20080309 

shubha pose la question : please help me out with this problem.
find the length of the common chord of the intersecting circles x2+y24x5=0
and x2+y22x+8y+9=0 Stephen La Rocque lui répond. 





Two circles and a triangle 
20080307 

Adrian pose la question : The vertices of a rightangled triangle are on a circle of radius R and the
sides of the triangle are tangent to another circle of radius r. If the lengths
of the sides about the right angle are 16 and 30, determine the value of
R+r Penny Nom lui répond. 





The diameter of a circle 
20080303 

Kathie pose la question : I know the length of the curved portion of a semicircle is 200 ft. but I need to find the diameter to get a total perimeter and area. How do I find the diameter to get the perimeter? Penny Nom lui répond. 





The perimeter of a sector of a circle 
20080228 

erica pose la question : What is the perimeter of a sector if the radius is 18 and the middle arc is 150? Penny Nom lui répond. 





The radius of a circle 
20080228 

SteVonee pose la question : Estimate the radius of a circle with the given circumference that is 192ft Penny Nom lui répond. 





The circumference and radius of a circle 
20080210 

Ray pose la question : How do you find the circumference or radius of an area presuming it is a circle. Or in other words how do you find the c or r given only the area is 50 sq metres Penny Nom lui répond. 





A chord of a circle 
20080207 

Mahesh pose la question : find the length of the cord intercepted by a circle with equation X2 +Y2 6X+4Y12=0 with a line of equation 4X3Y+2=0
Pl help me solve this problem
thanks
MNK Stephen La Rocque lui répond. 





The equation of a circle 
20080205 

aime pose la question : Find the equation of the circle tangent to 3x+4y15=0 at P1(1,3) and passing through P2(6,3) and P3(0,5)? Stephen La Rocque lui répond. 





The perimeter of a semicircle 
20080202 

Lisa pose la question : How do you find the perimeter of a semi circle when you are only given
the diameter, say 24 units? Penny Nom lui répond. 





Finding the area of an isosceles triangle given one angle and the inradius 
20080124 

Saurabh pose la question : Given an isosceles Triangle, whose one angle is 120 and inradius is √3. So area of triangle is? Stephen La Rocque lui répond. 





Two circles in a rectangle 
20080118 

Alex pose la question : One side of a rectangle is 10 and the other is x.
Two circles with equal radii are inscribed in the rectangle and like a Venn Diagram, the circles overlap.
Each circle touches the top and bottom of the rectangle and the left circle touches the left side of the rectangle and the right circle touches the right side of the triangle.
The distance between the centre of each circle is 2x/3.
Find x Penny Nom lui répond. 





A sector of a circle 
20080117 

Amandsa pose la question : What is the formula for finding the sector of a circle? Penny Nom lui répond. 





A large concrete shape 
20080116 

Keith pose la question : what is the cubic yards of an area that is not a perfect 1/4 circle?
The dimensions are 100ft. x 60ft. x 125ft. curcumferal arch x 3ft. depth? Stephen La Rocque lui répond. 





The area of a sector of a circle 
20080111 

Serenity pose la question : A denotes the area of a sector of a circle of radius r formed by the central angle theta.
Find the area A if r=10 meters and theta = 1/2 radians. Penny Nom lui répond. 





A circle of diameter 12 cm 
20080111 

Marcy pose la question : The diameter of the circle is 12cm. I need to convert the diameter to m2. Penny Nom lui répond. 





Seven circles in a circle 
20080110 

fae pose la question : what is the area of the remaining portion of a large circle with radius 12cm and the seven smaller and equal circles just fit inside? Penny Nom lui répond. 





A tangent to a circle 
20080104 

adam pose la question : Find a>0 so that the line y=x+a is a tangent to the circle x^2 +y^2=2. Stephen La Rocque and Harley Weston lui répond. 





How would one find the radius? 
20071229 

Ned pose la question : Given an arc with length of 192 inches (don't know chord length),
and arc height of 6 inches, how would one find the radius? Stephen La Rocque and Harley Weston lui répond. 





How many complete revolutions does each wheel make? 
20071228 

varoon pose la question : The wheels of a car are of diameter 80cm each. How many complete revolutions does each wheel make in 10 minutes when the car is travelling at a speed of 66kms per hour? Penny Nom lui répond. 





Circle area 
20071217 

Marlena pose la question : Ok, i do not see how to get the area of circles! they give you the circumfrance
which is 43.96cm and then u have to find the radius and area. I got the area right
which was 7cm but then i got 21.98 for a area and the real answer was 150.39cm
What did i do wrong? Penny Nom lui répond. 





The perimeter of circle 
20071215 

shaquilla pose la question : what is the perimeter of a circle. Penny Nom lui répond. 





A portion of a circle 
20071207 

Richard pose la question : please could you tell me the formula and answer to the following.
I have a circle portion with a radius of 150mm and an angle of 120 deg. If
an arc is drawn from one point to the other as the radii touch the circle
circumference, i need to know the area of the segment and the
formula to carry out the answer.
Many Thanks Penny Nom lui répond. 





A circle inscribed in a triangle 
20071206 

Linnea pose la question : I have a tringle with a circle inscribed in it. My teacher wants me to find the radius of the circle. This is what she gave me to work with. The triangle is ABC, AB = AC = 6, and BC = 4. She also told us to use A(squared) + B(squared) = C(squared). and that there are altitudes and and incenter. I have no idea how to do this. Harley Weston lui répond. 





A radius and a tangent to a circle 
20071204 

elizabeth pose la question : show that the radius of a circle meets a tangent line to the circle in a 90 degree angle.
hint: start by assuming they are not perpendicular and at a contradiction. Penny Nom lui répond. 





The diameter of a gasket 
20071201 

Jorge pose la question : I have an application where I am using a circular silicone gasket. I have the total length but would like to calculate the diameter with the given length. What formula should be used? We receive these gaskets in a roll and cut them about 21 inches and glue the ends together to make it one piece. I would prefer to purchase these already cut and glued but require a diameter. If I had the overall diameter from a 21 inch length gasket, I can look online for a part that comes close to the diameter.
Jorge Harley Weston lui répond. 





Dividing a circle 
20071123 

matt pose la question : hi. can you please send me a diagram of how to draw 3 lines in a circle to get 8 sections. Stephen La Rocque lui répond. 





Find the radius of a circle given the center and a point on the circle 
20071118 

Raymund pose la question : Find the radius if the center is at (0, 5) and one point on the circle is (2,3) Stephen La Rocque lui répond. 





The radius of an arch 
20071110 

Mark pose la question : How do you determine the raduis or diameter of a circle based on the folowing information:
1. The distance along the circle between two points is 35'2". This creates an arch.
2. The (chord) distance between the two points is 30'8".
3. The distance from the center of the chord (on a 90 degree) to the arch is 6'10 3/4". Harley Weston lui répond. 





Constructing the centre of a circle 
20071106 

Carolyn pose la question : I have a line segment AB. I need to divide a segment into 3 parts that are congruent. Please help how to divide it. The answer that I was given previous was not the way the teacher wanted it.
I also need information on how to find the center of a circle given an arc. Penny Nom lui répond. 





Great circles 
20071105 

Lindsay pose la question : Does a sphere have only ONE great circle? Explain? Stephen La Rocque lui répond. 





A circle is inscribed in a square 
20071028 

Carolyn pose la question : A circle is inscribed in a square. What percentage of the are of the square is inside the circle. Victoria West lui répond. 





Hexagon inscribed in a circle 
20071026 

VIVEK pose la question : what are the properties of a regular hexagon inscribed in a circle.
If the radius of the circle is given then how to find the side of the regular hexagon Stephen La Rocque lui répond. 





Arc length and height in a circle 
20071023 

Bruce pose la question : I have been trying to find a formula that relates height of a segment
from the bottommost point of a circle toward the center of the circle to
the corresponding distance along the circumference of the circle
(i.e. at the point on the circumference intersected by a line perpendicular
to that segment). The unknown variable is the height of the segment;
the known variables are the radius of the circle and the distance
along the circumference. Stephen La Rocque lui répond. 





How do you find the radius of a circle if you only know its area 
20071015 

s pose la question : how do you find the radius of a circle if you only know the area of the circle. Do you somehow
reverse the Pi formula. Penny Nom lui répond. 





Finding radius given chord length and distance to center 
20071004 

Venus pose la question : a chord of 48mm long is 7mm from the center of the circle. What is the radius of the circle? Stephen La Rocque lui répond. 





A sheet of corrugated iron 
20071003 

Ashutosh pose la question : A sheet of corrugated iron has corrugations based on the arc of a circle of radius of 3 cm and a central angle of 180 degrees. How many corrugations are formed when a flat sheet of steel 1 metre wide is bent to form a sheet of corrugated iron? Stephen La Rocque lui répond. 





Equation of a circle circumscribing a triangle with given vertices 
20071001 

Randy pose la question : How do I determine the equation of a circle when it is circumscribed by a
triangle whose vertices are (1, 6), (3, 2), and (2, 5)? Stephen La Rocque lui répond. 





Three circles 
20070929 

Kevin pose la question : 3 given circles of R80, R56 & R24 are all in contact. The 2 smaller ones are inscribed in the big one.
Find by calculation or graphically (both if possible) the radiusof a 3rd circle which will be in contact with all 3 given circles. Chris Fisher lui répond. 





A tangent line to a circle 
20070926 

Randy pose la question : Find the equation of the tangent line at coordinates (1 , 4)
on the circle x^2 + y^2  4x  21 = 0
I would like to learn the fastest way to relate any coordinates of a circle
to any possible point of tangency. Stephen La Rocque lui répond. 





A piece of wire is bent in the form of a circle 
20070924 

Renece pose la question : a piece of wire is bent in the form of a circle and it encloses an area of 154cm
a) calculate the radius of the circle
b) the circumference of the circle
use 22/7
The same piece of wire is then bent into a square
d) calculate the area enclosed by the square. Penny Nom lui répond. 





Finding the center of a circle that goes through three given points 
20070916 

Gary pose la question : I am given three points represented by their Latitude and Longitude. How do I determine the Latitude and Longitude of the center of a circle through the three given points?
The lat/lon of the three points are:
A. N 43 degrees 30.251 min. W 96 degrees 45.695 min.
B. N 43 degrees 30.006 min. W 96 degrees 45.082 min.
C. N 43 degrees 30.719 min. W 96 degrees 45.410 min.
Thanks. Stephen La Rocque lui répond. 





The area of half a circle 
20070914 

Heather pose la question : We need the formula for area of half circle please explain where each number comes from. Penny Nom lui répond. 





The circumference of a circle 
20070911 

annette pose la question : circumference of a 3.75 ft circle I have not done this in years and forgot how. Stephen la Rocque and Victoria West lui répond. 





The perimeter of a semicircle 
20070911 

Confused pose la question : What is the formula for the perimeter of a semicircle?
Can you please help me out!!!
I need this answer by tomorrow. Stephen la Rocque lui répond. 





Divide a circle into 5 equal parts 
20070907 

Kathy pose la question : How do you divide a circle into 5 equal parts using a protractor? Penny Nom lui répond. 





The area of a circle knowing only the length of a chord 
20070905 

James pose la question : I need some help in the right directions with a problem. I was presented with a problem where I need to find the area of a circle knowing only the length of a chord.
the is a circle in the center of a larger circle (which the size of either could change) the only thing that matter is that the chord is 100 ft long and rests on top of the smaller circle. Stephen la Rocque and Brennan Yaremko lui répond. 





Another circle problem 
20070827 

Lindsay pose la question : Hello. I'm trying to a math problem and have searched the internet for equations, but have come up empty handed. If you could help, that would be greatly appreciated!
The question is stated thus: Find the equation of the following circle:
the circle that passes through the origin and has intercepts equal to 1 and 2 on the x and yaxes respectively. Stephen La Rocque and Penny Nom lui répond. 





A circle and a tangent 
20070827 

Lindsay pose la question : Hello. I'm trying to do a math problem and have searched the internet for equations but have come up empty handed. If you could help, that would be greatly appreciated!
The problem is stated thus: A circle is tangent to the yaxis at y=3 and has one xintercept at x=1.
a. Determine the other xintercept
b. deduce the equation of the circle. Penny Nom lui répond. 





Reference angles 
20070825 

Jenny pose la question : find the reference angles for the angles given below, find the quadrants in which the angles lie
1. 0=6n/7
2. 0=3.3 Stephen La Rocque lui répond. 





Tangents to a circle 
20070818 

Laura pose la question : I have tangents from point A and B that intersect at C. A third tangent XY lies in between the two lines that I have already drawn. I measured the perimeter and then I drew another line that was tangent to the circle and was inside the two lines again and measured the perimeter again. The perimeters were the same but I don't know how to prove why this happened and write a theorem for it. Chris Fisher lui répond. 





Two circles C1 and C2 meet at the points A and B 
20070815 

Jerry pose la question : Two circles C1 and C2 meet at the points A and B. The tangent to C1 at A meets C2 at P. Point Q inside C1 lies on the circumference of C2. When produced, BQ meets C1 at S and PA produced at T. Prove that AS is parallel to PQ. Chris Fisher lui répond. 





Circle Geometry 
20070814 

Robin pose la question : In a triangle ABC, angle A=75 and B=60. A circle circumscribes the triangle. The tangents of the at points A and B meet in a point D outside the circle. Show that ABD is an isosceles triangle with a right angle at D. Diagram included. Stephen La Rocque lui répond. 





The equation of a circle 
20070812 

ranessa pose la question : Write the equation of the circle that satisfies the given condition.
C(0,8) ; R = 5 Penny Nom lui répond. 





Chords 
20070808 

HIMANSHU pose la question : we know that every straight line is the chord of a big circle. i have a circle
with radius 3.5feet. I want to know what is the length of the chord,
which would be a straight line. Stephen La Rocque lui répond. 





An athletic track 
20070730 

tammy pose la question : The inner boundary ABCDEF of an athletic track cinsists of two straight parts each 90m long and two semi circular ends as shown in the diagram.If the perimeter of the inner boundary is 400m, calculate the diameter AE of the inner semi circle.
Part 2. If the track is 3.5m wide an athlete starts the 400m run at X and remains in the outer lane . He finishes at Y(1) Calculate the outer diameter YZ
(2)The distance XY (take pie as 22/7) Penny Nom lui répond. 





Two chords in a circle 
20070729 

Jerry pose la question : Points A and C lie on the circumference of a circle. B is a point inside the circle. When produced, AB and CB meet the circumference at points E and D respectively. Prove that AB = CB, then EB = BD. Stephen La Rocque lui répond. 





Circle Geometry III 
20070717 

Sean pose la question : Two rays are drawn from the same point A outside a circle, and intersect the circle as shown in the picture. Prove that the measure of angle A is onehalf the difference between the measures of arcs BD and CE. Stephen La Rocque lui répond. 





The height of an arc at the center 
20070717 

Bob pose la question : I have a circle with a 26" radius and a cord whose length is 20". How can I find the height of the arc at the center point of the cord? Penny Nom lui répond. 





Circle Geometry II 
20070717 

Sean pose la question : Let M be a point outside a circle, and let a line through M be tangent to the circle at point P. Let the line through M and the center of the circle intersect the circle in points Q, R.
Prove that │PM│^{2} = │MQ│ x │MR│ Stephen La Rocque lui répond. 





Circle Geometry  Quadrilateral circumscribing a circle 
20070717 

Sean pose la question : Four lines are tangent to a circle that form a quadrilateral. It appears that the quadrilateral is a trapeziod but this is not a given. Prove that the combined lengths of two opposing sides of the quadrilateral are equal to the combined lengths of the other two opposing sides of the quadrilateral. Stephen La Rocque lui répond. 





Finding the area of a circle from its circumference 
20070716 

Amanda pose la question : what is the area of a circle with a circumference of 3000 metres? Stephen La Rocque lui répond. 





Any regular polygon inscribed in a circle 
20070712 

DJ pose la question : Circle with r=12" is inscribed in a regular octagon. What is the length of each octagon segment?
Note: Our answer works for any regular polygon inscribed in any circle. Stephen La Rocque lui répond. 





Length of a circle 
20070711 

Debra pose la question : i have a radius of 73 inches, i need to know the length of the circle please. Stephen La Rocque lui répond. 





Finding the radius of an inscribed circle 
20070705 

Maria pose la question : I need to find the radius of a circle which is inscribed inside an obtuse triangle ABC. I know all the angles and all the lengths of the triangle. Stephen La Rocque and Chris Fisher lui répond. 





The area of part of a circle 
20070621 

Sarah pose la question : Hi, I need help finding the area of a part of a circle that involves a
chord. I need this answer/help very soon if at all possible. I have
attached a drawing of what I am trying to solve. Thank you for your help!
Sarah! Penny Nom lui répond. 





Area of a circular garden 
20070618 

Cynthia pose la question : Hi is this the correct formula for this problem?
What is the approximate area of a circular garden that is 20 feet in
diameters? Stephen La Rocque lui répond. 





Babylonian geometry 
20070617 

marleen pose la question : The following problem and the solution were found on a Babylonian tablet dating from about 2600BC:
Problem:60 is the Circumference, 2 is the perpendicular, find the chord.
Solution:
Thou double 2 and get 4
Take 4 from 20, thou gettest 16
Square 16, thou gettest 256
Take 256 from 400, thou gettest 144
Whence the square root of 144, 12 is the chord.
Such is the procedure. Modern day mathematicians have reasoned that the Babylonian Mathematician who solved this problem assumed that the value of Pi is 3. By explaining in detail how the Babylonian Mathematician must have solved this problem, justify the reasoning of the modern mathematicians. Stephen La Rocque lui répond. 





What is the size of the circle it would make? 
20070613 

ed pose la question : i have a piece of sheet metal 56' 6" long what is the size of the circle it would make Penny Nom lui répond. 





A sequence of circles 
20070611 

Ann pose la question : Please help with solving the following problem!!!
A circle is inscribed in an equilateral triangle with a side of length 2.
Three circles are drawn externally tangent to this circle and internally
tangent to 2 sides of the triangle. 3 more circles are drawn externally
tantgent to these circles and internally tangent to 2 sides of the triangle. if
this process continued forever, what would be the sum of the areas of all the
circle? the answer 1 parent came up with was Pie over 2, but we don't
know how he did it. Can you please show the work or explain the answer to
this problem?
Thank you
Ann
p s my daughter is in 9th grade math. Steve La Rocque, Chris Fisher and Penny Nom lui répond. 





A circle and polygon with equal perimeters 
20070605 

matthew pose la question : Why does a circle have the largest area of any polygon when the perimeter is always 1000m for every polygon? Stephen La Rocque and Penny Nom lui répond. 





A circle inside a square 
20070531 

Mer pose la question : there is a circle inside a square... there is a shaded rectangle that measures 5mm X 10mm and they want to know what the radius is. The edge of the shaded rectangle touches a point on the circle. Penny Nom lui répond. 





A point on a semicircle 
20070528 

arun pose la question : a semi circle is drawn with ab as diameter from p a point on ab a line perpendicular to ab is drawn meeting circumference of semi circle at c, ac = 2cm, cd = 6cm find area of the semi circle? Penny Nom lui répond. 





Discovering the incircle of an irregular polygon 
20070525 

Joaquim pose la question : I've been searching in some books and many websites, but I couldn't find a formula or algorithm for discovering the incircle of an irregular polygon, could you please help me? Walter Whiteley lui répond. 





Relative sizes of circles 
20070522 

Griselda pose la question : There are 4 small circles inscribed in a bigger circle. The larger circle has a radius of 10 cm. Find the radius of the largest circle which will fit in the middle. Stephen La Rocque lui répond. 





Comparing the areas of various shapes 
20070516 

Kathy pose la question : If the perimeters are the same, which has the greater area, a circle, a square, an ellipse, or an octagon? Stephen La Rocque lui répond. 





Area of irregular surfaces 
20070509 

Dustan pose la question : I am working on a way to compute very accurate
areas for irregular surfaces by using the idea of a largest possible circle... Chris Fisher lui répond. 





Area of region between circle and inscribed octagon 
20070507 

amy pose la question : I have to find the area of the shaded region where there is an octagon inscribed in a circle
The radius is 4 inches. The shaded region is everything besides the octagon inside the circle.
How can I find the area of the shaded region?
Thank you! Stephen La Rocque lui répond. 





The circumference of part of a circle 
20070506 

Wallis pose la question : I have more then a quater of a circle, but less than half. What is the circumference if the two side are 7cm and the angle between them is 110 degrees? Penny Nom lui répond. 





A point inside a circle 
20070504 

edgemitter pose la question : There is a point inside a circle (but not in its center) where two perpendicular secants intersect, dividing the circle into four regions with different area. Calculate the area of the four regions Walter Whiteley lui répond. 





Two concentric circles form an annulus 
20070502 

A student pose la question : In the diagram below, two concentric circles form an annulus. The
vertical line is tangent to the inner circle, and forms the diameter of
a third circle.
Explain why the areas of the annulus and third circle are the same. Penny Nom lui répond. 





A square contains five circles with the same radius. 
20070421 

Jamie pose la question : A square has a side length on 1 m.
The square contains five circles with the same radius.
The centre of one circle is at the centre of the square and it touches the other four circles.
Each of the other four circles touches two sides of the square and the center circle.
Find the radius. Penny Nom lui répond. 





Constructing an octagonal deck around a circular pool 
20070420 

Cliff pose la question : [I am building an] octagonal desk encompassing 17 foot diameter circle for pool.
I have seen other octagonal calculations but none of these tell me how much allowance for a circle to fit within the octagon without losing the circle edge can anyone help
thanks cliff Stephen La Rocque lui répond. 





Two concentric circles 
20070419 

James pose la question : Two concentric circles have a chord running through the outer one. The chord is the tangent of the inner circle and is 14 cm.The outer circle is shaded and the inner circle is not. Find the exact area of the shaded region without using a calculator. Stephen La Rocque lui répond. 





Four semicircles are drawn inside a square 
20070419 

James pose la question : Four semicircles are drawn inside a square, with the diameter being the length of the square.The overlapping portion of the semicircles are shaded. What fraction is shaded? Penny Nom lui répond. 





Two tangents to a circle 
20070417 

Doug pose la question : Two distinct, nonparallel lines are tangen to a circle. The measurement of the angle between the two lines is 54 degrees (angle QVP).
Suppose the diameter of the circle is 2 cm. What is the distance VP? Suppose the distance VP is 3.93 cm. What is the diameter of the circle? Find a formula for d, the diameter of the circle, in terms of VP.
Find a formula for VP in terms of d, the diameter of the circle. Stephen La Rocque lui répond. 





Intersection of a line and a circle 
20070412 

gaby pose la question : The sum of two numbers is 9. The sum of the squares of the two numbers is 41. Find the numbers. Steve La Rocque and Melanie Tyrer lui répond. 





An arc shaped groove into a peice of metal 
20070412 

daniel pose la question : hello i work at an engineering workshop the other night i was asked to machine an arc shaped groove into a piece of metal the cord length was 6 mm and the height from the middle of the cord to the arc was 1mm i was hoping to find the diameter of the cutter needed to do the job and also the formula to work out how to find the diameter. i believe it is 10mm dia thankyou for your time and knowledge Stephen La Rocque lui répond. 





A cabinet with an arched front 
20070409 

Joe pose la question : I am building an arched front cabinet that is 71 inches wide, 12 inches deep at both ends
and 16 inches deep at the center. To accurately build this cabinet I need to known the radius of
the circle that would form that arch.
Thanks,
Joe Penny Nom lui répond. 





Area of circles within a circle 
20070408 

Avaline pose la question : Imagine that there are four small circles inscribed in a bigger circle. The 4 small circles are shaded. What is the ratio of the area of the shaded region to the area of the unshaded region? Stephen La Rocque lui répond. 





An arched opening for a large doorway 
20070408 

Richard pose la question : I am trying to build an arched opening for a large doorway...I know the vertical sides of the opening to be 8'9" from the floor to the lowest point of the arch on each side...I know it is 15 1/2" from the center horizontal point to the top of the arc...I know the vertical sides are 11'11" apart...what I need to know is the radius to create the proper arc. Can you help? Stephen La Rocque lui répond. 





Radius of a circle in a square 
20070405 

Lori pose la question : A circle is inscribed in a square. What is the radius of the circle?
If there is a small rectangle with a 2 ft. top and a 1ft side at the left in the
square touching the corner of the circle. Stephen La Rocque and Penny Nom lui répond. 





A triangular prism 
20070326 

Tom pose la question : Hi, I need to find a container in the shape of a triangular prism that will fit
four table tennis balls (this is for a math project!). These balls have a
diameter of 4cm, so a radius of 2. I know that the formula for finding
an incircle from a triangle is: radius of incircle =
2area of triangle / perimeter of triangle
But I need to know the length of one side of the triangle from the incircle
(the triangle needs to be equalateral).
Can you help me find a formula for this?
Thanks so much!
Tom Penny Nom lui répond. 





Inscribed square in inscribed circle 
20070325 

Confuzzled pose la question : "The largest possible circle is drawn inside a square. Then the largest possible square is drawn inside this circle. What is the area of the inner square as a fraction of the area of the outer square?"
This is a question from the Grade 8 Gauss contest and I don't know how to work it out without drawing it. My teacher says it's possible but I still don't get it. Please help!!! Stephen La Rocque lui répond. 





Circles and chords 
20070315 

Henry pose la question : Where do you place a chord in a circle such that it divides the area
of the circle 1/3 and 2/3? Also, what is the length of the chord? Stephen La Rocque lui répond. 





circles 
20070306 

chetna pose la question : A large circle has a radius of 10cm.Given four congruent circles tangent to one another within the large circle what is the radius of the largest circle which will fit in the middle ? Stephen La Rocque lui répond. 





Cutting the top off a circle 
20070225 

Daniel pose la question : If a circle as a diameter of D I cut off a straight part at C from the top What is the formula to find the area of the left over part? Penny Nom lui répond. 





Circles 
20070222 

Erika pose la question : I have a research paper due on real life uses of conic sections I've looked through all your conic topics and uses of them, but and i cant seem to find real life uses for circles. What are real life uses of circles? Penny Nom lui répond. 





A pentagon inscribed in a circle 
20070222 

Amanda pose la question : Find the formula for calculating the length of the side of a pentagon given the radius of the circle that encloses it. Once you find the formula, find the length of the side of a pentagon which is enclosed in a circle 12 cm in diameter. So I need to know the formula, and the length of the side of the pentagon. Thank you!! Penny Nom lui répond. 





A circle tangent problem 
20070221 

Jason pose la question : Please help me to solve this problem. Thank you very much. Find the equation of the circle tangent to 3x+y+14=0 and x+3y+10=0 with radius squareroot of 10. Stephen La Rocque and Penny Nom lui répond. 





Finding the equation of the circle 
20070220 

ning pose la question : Given the radius of a circle square root of 10 tangent to the line 3x+y+19 = 0 and passing through (0,3), how can i solve the equation of circle? thank you... Chris Fisher, Steve La Rocque and Penny Nom lui répond. 





Two concentric circles 
20070211 

maria pose la question : i have a problem with this quadratic word problem which i am trying to solve it but couldn,t get it please help me to solve this question Two concentric circles are drawn, the radius of one being 2cm greater than that of the other. The area of the ring enclosed between the two circles is one quarter of the area of the smaller circle.Calculate the radii of the circles,correct to three significant figures. (Don,t substitute for pie) Stephen La Rocque lui répond. 





Perimeter of an octagon inside a circle 
20070208 

Courtney pose la question : a regular octagon is inscribed in a circle with a radius of 12 cm. find the perimeter of the octagon? Stephen La Rocque lui répond. 





A triangle inscribed in a semicircle 
20070206 

Benneth pose la question : Consider a triangle inscribed in a semicircle with a radius of R. What are th possible perimeters for the triagle? And the areas? Penny Nom lui répond. 





A rectangle inscribed in a circle 
20070204 

Benneth pose la question : Consider a rectangle with radius R inscribed in a circle. What are the possible areas of the rectangle? Steve La Rocque and Walter Whiteley lui répond. 





The centre and radius of a circle 
20070127 

A student pose la question : x^2+y^2=121 is the equation of the Circle C
(1) Write down the center and the radius of C. Stephen La Rocque lui répond. 





A circle inscribed in an octagon 
20070125 

Anna pose la question : If I know that the sides of my octagon are 8 units, how do I determine the radius of an inscribed circle? Penny Nom lui répond. 





Splitting A Circle Evenly 
20061220 

Joe pose la question : I'm trying to make a game board and instead of having it square, I would like to give it a curve (the game is Parcheesi). The attached diagram is pretty much completed (done in AutoCAD). What I would like to know is how to manually find the points that intersect the red line. In other words, evenly split the semicircle into 8 pieces. Penny Nom lui répond. 





A regular polygon inscribed in a circle 
20061219 

Katy pose la question : If a regular hexagon is inscribed in a circle of radius 6.72 centimeters, find the length of one side of the pentagon. How would I got about explaining this? Penny Nom lui répond. 





Circles and polygons 
20061211 

Irene pose la question : Can you define a circle as a polygon with an infinite number of sides which are infinitely small? If you can, can you then define a cylinder as a prism? The sides would be rectangles or parallelograms with one length infinitely small? Chris Fisher lui répond. 





Area of a circle 
20061201 

Lisa pose la question : i have 24m of fence how would i find out the area of a circle using this 24m of fence? Stephen La Rocque lui répond. 





Sectors of a circle 
20061130 

Maithreyi pose la question : A circle of diameter 21m is divided into three sectors with central angles 60degree,120degree and 180degree. Find the area of each sector? Stephen La Rocque lui répond. 





Creating a triangle in a circle 
20061128 

Dirk pose la question : My daughter has a school project where she must draw a circle and then draw an equilateral triangle inside the circle. She said you have to identify six points on the circle to correctly draw the triangle. How do you accomplish this? Penny Nom lui répond. 





The area of a semicircle 
20061125 

Melinda pose la question : If the radius of a semicircle is 9ft what is the area? Karen McIver and Penny Nom lui répond. 





Circle geometry 
20061119 

Namrata pose la question : AB is a diameter and AC IS A CHORD OF A CIRCLE SUCH THAT angle=30. the tangent at C intersect AB produced in a pointD. Prove that BC=BD. Stephen La Rocque lui répond. 





Conic sections 
20061119 

Joyce pose la question : My son has a project on conic sections. I need the following information on Parabola, Circle, ellipse,and hyperbola. He can't find the following information for each conic section: equations with explanations, four uses for each shape and Shape explanation. Penny Nom lui répond. 





The area of regular pentagon inscribed in a circle 
20061012 

Admire pose la question : i need help on how to find area of regular pentagon inscribed in a circle of radius 8cm Stephen La Rocque and Penny Nom lui répond. 





Is a circle a regular shape? 
20061010 

David pose la question : Is a circle a regular shape or an irregular shape? Stephen La Rocque lui répond. 





Two word problems 
20061002 

Eve pose la question :
1. A surveyor's map shows a plan for the rectangular rose garden whose area is
a^{2}+25ab350b^{2}. Find an algebraic expression for the length and width. If a=20 ft and b=10 feet, find the actual dimensions of the garden.
2.A square is enclosed in a circle. The area of the square is (4r^{2}32r+64)sq cm and the area of the circle is 484r^{2} sq cm. Write a polynomial in factored form to represent the difference of the two areas.
Stephen La Rocque lui répond. 





The area of a circle 
20061002 

A student pose la question : Calculate the area of a circle whose radius is 75 meters? Stephen La Rocque lui répond. 





An equilateral triangle has been wedged in between two circles. 
20060922 

Kim pose la question :
An equilateral triangle has been wedged in between two circles. How does the diameter of the smaller circle compare to the diameter of the larger circle.
image: circle inside of an equilateral triangle touching all sides of the triangle; both the triangle and the circle inside are placed into a larger circle where the triangle vertices all touch the circle
Penny Nom lui répond. 





A concrete semicircle 
20060815 

John pose la question : I have to figure out how many yards of concrete I need for a semicircle. I have a radius of 21 feet and the concrete is 4" thick. I took 3.14 x (21)^2 then divided by 40 to get how many yards of concrete but that doesn't seem right. Penny Nom lui répond. 





What is the area of the circle? 
20060719 

Nana pose la question : the circle is tangent to sides BC and AD of the 8 by 12 rectangle, ABCD. What is the area of the circle? Stephen La Rocque lui répond. 





A tangent to a circle 
20060705 

Izumi pose la question :
I have problems finding the point of tangency between the circle C
x^{2} + y^{2} + 4x  6y  12 = 0
and the tangential line that passes through the point P (6, 1).
Stephen La Rocque lui répond. 





A 9 foot diameter circle 
20060702 

Lisa pose la question : How do I calculate 9 foot diameter measurement in total feet?? Stephen La Rocque lui répond. 





Marking out a circle 
20060628 

Peter pose la question : given a straight line. how do i work out the off sets ( at right angles) at several intermediate points. to set out a 5.0m arc that has a 18.0m radius. Stephen La Rocque and Penny Nom lui répond. 





The area of part of a circle 
20060529 

Larry pose la question : need to find area of a circle between a given line (cord) to the circumference of the circle (see attachment). I often review blue prints of homes and many times have to know the area the home. Stephen La Rocque and Penny Nom lui répond. 





The length of the diameter 
20060518 

Steven pose la question : A circle has a circumference of 312in. Find the length of its diameter to the nearest integer? Penny Nom lui répond. 





The last slice of pizza 
20060427 

Lori pose la question : I have a pizza. The radius is 10 inches long.The pizza was cut into 16 equal slices. When one slice was left, my sister and I both wanted it, so we agreed to cut it in half, but I like the crust more than she does, so we decided to cut it the "other way." In other words, the two pieces would not be symmetrical. The inside piece would contain all topping, and the outer piece would contain some topping and some crust.
How far up the radius from the center of the circle will I need to cut so we will both have an equal area of pizza? Stephen La Rocque lui répond. 





Geometry proof 
20060423 

Jade pose la question : From a point P outside a circle with centre O, tangents are drawn to meet the circle at A and B.
a) Prove that PO is the right bisector of the chord AB.
b) Prove that Stephen La Rocque lui répond. 





Which has more pizza? 
20060419 

Kristine pose la question : Which has more area: a round pizza that is 16 inches in diameter or three square pieces of pizza that are 8.5 inches on each side? Stephen La Rocque lui répond. 





Three circles inside a larger circle 
20060416 

Meghan pose la question : Given three congruent circles tangent to one another (radii = 1), what is the radius of a circle circumscribed around them?
Stephen La Rocque lui répond. 





Overlapping area of two circles 
20060415 

Jade pose la question : Given two identical circles where the radius (6 units) is the distance between the centers, what is the area of the overlapping region?
Stephen La Rocque lui répond. 





An epicycloid 
20060410 

Sharon pose la question : What is the name of the curve formed by a point on the circumference of a circle that rolls on the outside of a fixed circle? This curve is used in the study of gears. Stephen La Rocque and Penny Nom lui répond. 





Two circles 
20060407 

Louisa pose la question : One circle of radius 7cm is touching another circle of radius 4cm. These circles are on a line and the problem is to find the length AB where A is the point marking the bottom of the radius of one circle and B is the point marking the bottom of the radius of the other circle. Stephen La Rocque lui répond. 





A square in a circle 
20060405 

Lisa pose la question : A square is inscribed in a circle. Determine the percent of the circle's area that is outside the square. Stephen La Rocque lui répond. 





The centre and radius of a circle 
20060402 

Kaye pose la question : I need to calculate Dimension E and F. I am given A, B, C, (or over all A+B+C), D, G. The radius is one continuous unknown radius.
Example: A = 23.50
B = 35.50
C = 0.50
D = 11.50
G = 23.50
I have calculated this for angles but my mind is drawing a blank for the radius calculation. I can draw it but I need to put into Excel spreadsheet.
Harley Weston lui répond. 





Can one divide a circle into 4.5 parts 
20060330 

Chris pose la question : If it is possible, can one divide a circle into say, 4.5 parts (with 4 equal parts and a half part)?
Or for that matter, for any integer, n, into n/2 parts as above?] Walter Whiteley lui répond. 





The square footage of an area in my backyard 
20060317 

Kim pose la question : I need to find out how to calculate the square footage of an area in my backyard that is in the shape of a "slice of pie". There are two sides that are straight lines that come together at the top to form a point, and then at the bottom is a curved line that joins the two other lines together. I need to figure out how to calculate the square footage that is inside the area. Penny Nom lui répond. 





If a circle is elongated into an oval .. 
20060316 

Bruce pose la question : If a circle is elongated into an oval, with constant circumference, does the area remain constant? Walter Whiteley lui répond. 





A circle containing two points 
20060313 

Skye pose la question : Write the equation of a circle having area 15pi and containing the points (1, 5) and
(1, 9). Penny Nom lui répond. 





What names are known for the quarter circle shape? 
20060306 

Christina pose la question : What names are known for the quarter circle shape? Stephen La Rocque and Penny Nom lui répond. 





Make 2 rows of 4 circles with only 6 circles 
20060131 

Sarah pose la question : Moving as many circles as you need, make 2 rows of 4 circles only having 6 circles? Chris Fisher lui répond. 





Sectors and arcs 
20060125 

Wael pose la question : How is the area of an arc (alpha*pi*r squared/360) derived?
How is the length of an arc (alpha*pi*r/180) derived? Penny Nom lui répond. 





A circle problem 
20060123 

Matyan pose la question :
Find the standard equation of the circle that passes through the points (0,4) and (3,7) with center on the line
2xy+4=0.
I've tried substituting the two points to the general equation of a circle, but I can't solve it without a third equation. The problem here is I don't really know how to use the given line of 2xy+4=0. Please help. Thank you.
Penny Nom lui répond. 





The circumference of a larger circle is twice the circumference of a smaller circle. 
20060120 

Amanda pose la question : The circumference of a larger circle is twice the circumference of a smaller circle. What is the ratio of the radius of the smaller circle to the diameter of the larger circle? Penny Nom lui répond. 





A sequence of circles and tangents 
20060116 

Paul pose la question : Consider a circle whose center is (2,2) and whose radius is 1, and the
straight line that goes through the origin and that is tangent to this
circle so that the intersection between them is as shown in the attached
picture. With this new point we make a new circle whose radius is half
of the first one, and we calculate the corresponding intersection point
with the same suppositions as in the first case. We repeat the process
to the infinite. Find the distance between the center of the circle in
the infinite and the origin (point (0,0)). Chris Fisher lui répond. 





The area of a sector of a circle 
20060102 

Natashia pose la question : How do you find the area of a shaded sector of a circle? Penny Nom lui répond. 





A goat is tied to the corner of a 50 ft square outbuilding 
20051224 

Danielle pose la question : Topic: A goat is tied to the corner of a 50 ft square outbuilding with a 40 ft. rope.
a) What is the measure of the partial circumference created as the goat walks at the full length of the rope?
b) Since the goat is trimming the grass from part of the outbuilding, how much of the perimeter of the outbuilding will the building owner have to trim? Penny Nom lui répond. 





A regular octagon is inscribed in a circle 
20051213 

Carlin pose la question : A regular octagon is inscribed in a circle of radius 15.8 cm. What is the perimeter of the octagon? Penny Nom lui répond. 





Four tangent circles 
20051206 

Ananth pose la question :
I have one bigger circle A with radius 15.
Inside this bigger circle i have another circle B with radius 3 which touch this bigger circle. Have another circle C with radius 4 which touches A and B. I would like to draw a biggest circle which touches A,B and C.
Chris Fisher lui répond. 





Divide a circle into eleven parts 
20051107 

Dean pose la question : I would like to know how to divide a circle into eleven parts using only four lines. Claude Tardif lui répond. 





The length of a chord 
20051103 

Sue pose la question : How do you determine the length of a chord when given the diameter of the circle (1.6m) and that the angle = 7π/8 Penny Nom lui répond. 





A line that intersects a circle 
20051018 

Bruce pose la question : I would like to solve the following problem illustrated below. How do you calculate the length of a line that intersects a circle. Penny Nom lui répond. 





The area of an irregular semicircle 
20051014 

Bob pose la question : Is there a way to compute the area of an irregular semicircle i.e. one in which the arc length is not determined by the diameter; and is therefore not technically any part circular  yet still possessing an arched side? Penny Nom lui répond. 





Calculer la clé 
20050929 

Un eleve pose la question : Chaque individu a un numéro INSEE de 13 chiffres auquels est adjointe une clé de deux chiffres.
voici comment est calculée cette clé : Claude Tardif lui répond. 





The length of a circle's chord 
20050928 

A homebuilder pose la question : find the length of a circle's chord with a known arc length and radius/diameter lengths. Penny Nom lui répond. 





The radius of an arc 
20050819 

Jared pose la question : I need to be able to calculate the radius of an arc on an existing structure (Supports for Fifth Ave Dimensional Text). I have the overall length of this structure, but, the complication I believe lies in the fact that it is a curve mounted onto a flat section of wall on either side of a very mild curve, therefore, measuring the middle of the wall to the top of the arc does me little good...The reason I need this is to be able to replicate the above curve on a similar structure to be mounted below it...Also, because the client wants the structure mounted on the inside of the opening below the existing, the beginning and end point of the new structure would be lower than the existing, so, I do not believe that it is possible to exactly replicate the radius of the above curve? Penny lui répond. 





Is 360 Really the correct value? 
20050815 

Jack pose la question : Considering the circumference of a "Perfect Circle" with a Diameter of 1 meter would be something like 3.14 meters, why do we use the number 360 to represent the number of degrees within that circumference?
Would it not make more sense to express the degrees in reference to the relationship to the diameter as related to pi?
That is, let's just say our "Perfect Circle" has a circumference of 3.14 meters, therefore, what we now consider as due east would change from 90 Degrees to 78.5 Degrees. Penny Nom lui répond. 





Framing an arched wall 
20050812 

Mike pose la question : I'm framing a building wall with a curved (arcing) top section. The radius of the section is 74'6" with a height above finish floor of 16'0". The horizontal run of the arced section is 23' 1 1/2" with a low height above finish floor of 12'4". If I start with a 16' stud at the high end how long are the subsequent studs if they are on 16" centers? Short of laying this out on a tennis court how can I work out the lengths of the studs? Penny Nom lui répond. 





Two tangents to a circle 
20050618 

Tej pose la question : The tangents drawn from points M and N of a circle
having centre O intersect each other at point P. If
angle MPN=60 degrees, NM=10, then find the radius of
the circle and Area of quadrilateral OMPN. Penny Nom lui répond. 





Difference in latitude 
20050405 

Gretel pose la question : Assuming the the earth is a sphere of radius 6378 kilometers, what is the difference in latitude of two cities, one of which is 400 kilometers due north of the other? 500 kilometers? Penny Nom lui répond. 





Two overlapping circles 
20050320 

Safi pose la question : I have a problem to calculate the area of two overlapping circles because two circles are overlap then how i calculate the overlap area to subtract from the area of both circle. Penny Nom lui répond. 





Tangents to a circle 
20050319 

Sue pose la question :
You're given the equation to a circle (x3)^{2 }+ (y3)^{2} = 4
and you need to do 3 things:
1. Find a point on the circle
2. Construct an equation for a tangent line to the circle and through the point
3. Plot the circle, point and the tangent line on one graph
Penny Nom lui répond. 





Three tangent circles 
20050125 

Kate pose la question : Two circles, C1 and C2, touch each other externally; and the line l is a common tangent. The line m is parallel to l and touches the two circls C1 and C3. The three circles are mutually tangent. If the radius of C2 is 9 and if the radius of C3 is 4, what is the radius of C1? Chris Fisher lui répond. 





The diameter of a 800 km circle 
20050122 

Mechelle pose la question : What is the diameter of a 800 km circle? Penny Nom lui répond. 





The radius of a circle 
20050118 

A student pose la question : find the radius of a circle whose area is 1256sq cm.Use pi as an appoximation for pi. Penny Nom lui répond. 





A nonrerctangular lot 
20050118 

EM pose la question : One corner of a 60X120 foot lot, otherwise rectangular, is a curve with a radius of 20 feet and a central angle of 90 degrees. What is the area? Penny Nom lui répond. 





The length of a chord 
20050113 

A parent pose la question : Does anyone have a formula for calculating the chord length for a segment of a circle when you know the radius and the enclosed angle or radian ? Penny Nom lui répond. 





Arcs and chords 
20050109 

Aniesha pose la question : A chord of a circle is 48 centimeters long and is 10 centimeters from the center of the circle. Find the radius? Penny Nom lui répond. 





A line from the center of the patch to the periphery 
20050101 

Sandrine pose la question : I am currently researching a patch disease of grasses. These patches are roughly circular. I need a term for a line from the center of the patch to the periphery. Since the patches are not perfectly circular, my supervisors tell me I cannot use the word 'radius'. What else could I use? Denis Hanson and Harley Weston lui répond. 





Irrigation and a sector of a circle 
20041223 

Chuck pose la question : A friend of mine is a farmer and uses Pivots to irrigate portions of his land. The crop rows are in straight lines that all form chords of a large circle. The intent is to determine area between any two "boundary" rows expressed in acres. Harley Weston lui répond. 





A regular hexagon is inscribed in a circle. 
20041208 

Abraham pose la question : A regular hexagon is inscribed in a circle. What is the ratio of the length of a side of the hexagon to the minor arc that it intercepts?
(1) pi/6
(2) 3/6
(3) 3/pi (This is the correct answer.)
(4) 6/pi
I found the length of the minor arc to be (pi)(r)/3 by doing a sixth of the circumference(2pi r).But I can't find the length of the radius to finish off the problem. If I knew the radius I would then plug it into the above and then use the radius again to be the length of the side because the triangle(one of the six of a hexagon) is equilateral. But can you show me how to get the radius to be 3? Thank you so much.
Walter Whiteley lui répond. 





A belt around two pulleys 
20041207 

Ian pose la question : a belt is stretched around two pulleys whose centers are d units apart and whose radii are R and r respectively (obviously R+r<d). the challenge is to find the length of the belt, l as a formula in terms of R, r, and d only. Penny Nom lui répond. 





An arc of a circle 
20041205 

Ruben pose la question : i have an arc 55 inches wide, 12 inches high at the centerline of the arc. how can i determine the diameter of the circle that would correspond to the arc. Penny Nom lui répond. 





Largest square inside a circle 
20041025 

Bob pose la question : my granddaughter asked
what is the largest size square in inches
would fit in a 60 inch circle?
I believe it to be around 42.3 inches but
would like to teach her how to do it mathematically. Penny Nom lui répond. 





Perimeter and area of a semi_circle 
20040918 

A student pose la question : I want to know how to find the perimeter and area of a semicircle and a quartercircle. Penny Nom lui répond. 





The radius of a circle 
20040824 

Peter pose la question : If you slice any circle with a line, and call the distance of the line between intersections the "y" length and the perpendicular length to the shorter side of the curve the "x" length, what is the resulting equation for the radius? Penny Nom lui répond. 





The railing around a pool 
20040726 

Bob pose la question : I have a 15' circular above ground pool. Around the perimeter of the pool are eleven (11) sections of railing. Each rail has 5 slots at each end for pins. I have calculated that the length of the arc under the railing to be 51.4". what I am trying to determine is the distance between the end points of the arc so that I can figure out which slot to use in the rails without going round and round the pool moving and removing the rails until they finally fit. Been there, done that, no fun. Penny Nom lui répond. 





The circle through three points 
20040706 

Jim pose la question : I am a student trying to solve math problem. I'd like to calculate the radius of the circle that exactly fits any three points. If the points are (X1,Y1), (X2,Y2), and (X3,Y3), what is the radius of the circle that contains those three points? Penny Nom lui répond. 





The center of a circle 
20040526 

Wan pose la question : I am trying to find the radius of an arc. The only things i know about the arc is all referenced from the line of tangency to the arc. on both sides i have a differnt horizontal perpendicular distance to the point of tangency.
left side * right side (*=point of tangency). Then i have 2 difference vertical perpendicular distance of the end points to the line of tangency. I know it sounds very bad in text but this is all i know about the arc. Can you help me find the radius? Penny Nom lui répond. 





Circles in a hexagon 
20040411 

Crystal pose la question : step by step can you show me how to calculate the area of the region inside the hexagon but outside the seven circles. given the radius of each circle is one inch Penny Nom lui répond. 





Numbers around a circle 
20040328 

Rebecca pose la question : my maths question is use the numbers 1,2,3,4,5,6 and 7 place each number in a circle so each line adds up to 12. There are seven circles, six on the outside and one in the middle. Each number lines up with the middle number and the outside numbers line up with the one directly across from it as if a line was going through the middle number circle. Penny Nom lui répond. 





The radius of a circle 
20040306 

A student pose la question : what is the radius of a circle with the circumference of 12 inches? Penny Nom lui répond. 





A geometry problem 
20040304 

Jennifer pose la question : I need help with this problem: Square ABCD has side length 2. A semicircle with diameter AB is constructed inside the square, and the tangent to the semicircle from C intersects side AD at E. What is the exact length of CE?o Chris Fisher lui répond. 





Areas, perimeters and derivatives 
20040215 

Geoff pose la question : A recent lecture in my calculus class led me to realize that the derivative of the area of a circle, with respect to the radius is equal to the circumfrence. This also holds true for the relationship between the volume of a sphere and the surface area of that sphere:
why do these hold true? why is it only for circular objects? Harley Weston lui répond. 





An arc on a train track 
20040215 

A student pose la question : I'm trying to build a route in a train simulator program. I have a curve to the right (an arc, in other words) with a length of 25 meters and the radius is 1,500 meters. Let's say point P is the beginning of the curve (arc) and point Q is the end point of the arc. Then picture a tangent to point P. I need to find the length of a line perpendicular to that tangent that runs to point Q (the end of the curve/arc). Penny Nom lui répond. 





The sides of a circle 
20040107 

Helena pose la question : My name is Helena and I am 10 years old. On a resent math exam I was asked
the question" How many sides does a circle have?" and I wrote down none. The
teacher said the answer was one side. Chris Fisher lui répond. 





A locus 
20031202 

Tash pose la question :
Question:
a)Find the equation of the locus of the point P which moves so that its distance from A(1,2) is always three times its distance from B(5,6)
b) Show that this locus is a circle and states the coordinates of its centre and the length of its radius
Penny Nom lui répond. 





The length of a chord 
20031103 

David pose la question : When Radius=400.00' and Arc=130.58' what is the Cord distance in feet? Penny Nom lui répond. 





A circle around an irregular polygon 
20031103 

Dale pose la question : How do I find the properties of a circle that is drawn around an irregular polygon of (n) sides with the lenghts of each side given and all end points of the polygon lye on the circumferance of the circle? Chris Fisher lui répond. 





Two chords 
20031007 

Lori pose la question : Chords AB and CD of circle O intersect at E. If AE=4, AB=5, CE=2, Find ED. Penny Nom lui répond. 





The general equation for a sphere 
20030911 

Jaidev pose la question : Is there any general equation for a sphere? Penny Nom lui répond. 





A theorem in geometry 
20030902 

Diego pose la question : Please refer to figure in attached file. P is a point on the chord AB of a circle such that the tangent PT which touches the circle at T is equal to AB. How do we prove that PT^{2} = AP x BP. Dieter Ruoff and Penny Nom lui répond. 





A geometry problem 
20030708 

Chris pose la question : My name is Chris, I work for a custom fabricator company. I am needing a formula for the Height (H) shown in the attached picture. The picture shows dimensions for my current application. If you could please, assign variables to the dimensions. Harley Weston lui répond. 





Definitions and descriptions 
20030608 

Tammy pose la question : MY DAUGHTERS TEACHER ASKED HER TO GIVE BOTH A DESCRIPTION AND A DEFINITION OF THE FOLLOWING ... CIRCLE, SQUARE, TRIANGLE,HEXAGON...... THE LIST GOES ON. WHAT IS THE DIFFERENCE BETWEEN DEFINITION AND DESCRIPTION ? DO A CIRCLE FOR AN EXAMPLE PLEASE. Penny Nom lui répond. 





Circumference 
20030509 

A parent pose la question : Find the circumference use 3 1/7 for pi
1. r= 28 ft. 2. D=98 cm Penny Nom lui répond. 





A circle, tangent to two circles and a line 
20030430 

Keith pose la question : I have a horizontal line (that is treated as a datum line or the X axis), with two circles having their center points at different heights from that line (X1,Y1 & X2,Y2). The two circles are also at different diameters (R1 & R2). Both circles and the line (XAxis) do not intersect nor are they tangent. My goal is to determine the maximum diameter of an inscribed circle that will fit between all three. Chris Fisher and Harley Weston lui répond. 





A tangent to a circle 
20030418 

Lech pose la question : The line with equation y=mx is a tangent to the circle with equation x2+y26x6y+17=0. Find the possible values of m. Harley Weston lui répond. 





Divide a circle in 8 equal pieces 
20030404 

Naomi pose la question : I have to divide a circle in 8 equal pieces but can only cut 3 times can you please help me Penny Nom lui répond. 





A triangle and a circle 
20030321 

Jynks pose la question : We need a formula that we can use to figure this out for work. We aren't math wiz's or students. Basically we know 3 points in space of a triangle, we know the length of each side and the length of the line from apex to base line. Each point of the base line ends upon the circumference of a circle. IS three a way to work out the radius of that circle. Penny Nom lui répond. 





An arc of a circle 
20030312 

Melissa pose la question : A strip of wood is 16 ft. long and is bent in the arc of a circle. Two radii, from the center of the circle to the ends of the arc, form a right angle. What is the approximate distance from one end of the wooden arc to the other? Penny Nom lui répond. 





I have three circles... 
20030130 

Tony pose la question : I HAVE THREE CIRCLE THAT IS CIRCLE TOGETHER: IN CIRCLE A, THE NUMBERS ARE: 11 I KNOW IS IN CIRCLE A, BUT I HAVE THE: 5 THAT IN A AND C, I HAVE THE 2 IN THE CIRCLE C AND B AND AND A, THE CIRCLE C I KNOW THAT 10 IS IN THE CIRCLE THE 4 IN CIRCLE A: AND B: IN CIRCLE B, I KNOW NUMBER 13 IS IN CIRCLE B; BUT I HAVE THE 3 IN CIRCLE B AND C AND I HAVE THE 2 IN CIRCLE B AND C AND A ,THE 4 IN CIRCLE B AND A. HOW DO I FIND THE SUM IN CIRCLE C AND IN B IN BOTH CIRCLE A AND B AND B AND C NOT IN CIRCLE B, AND NOT CIRCLE C. Penny Nom lui répond. 





Constructing a tangent to two circles 
20021128 

Tom pose la question : I have two circles, different sizes a known distance from each other. We know the radii of the circles. How do I construct a line that is tangent to both circles relative to the segment that connects the centers of both circles? Chris Fisher and Penny Nom lui répond. 





Subdividing a circle 
20021111 

David pose la question : Say you have a cirlcle. Then you draw 2 dots on the circle. Then you connect the dots with lines. The circle is divided into 2 parts. If you do the same with 3 dots and connect each dot to each dot with a line then you get a circle with 4 parts. 4 dots with lines connecting all (6 lines) = 8 parts.... Claude Tardif lui répond. 





A Circle is evenly divided into six equal triangles 
20020916 

Marilynn pose la question : A Circle is evenly divided into six equal triangles leaving an area between the outside of the circle and the one side of the triangle. This area is measured as 3.14. What is the length of the radius, one line on the triangle? Paul Betts lui répond. 





What really is pi? 
20020905 

Rachel pose la question : what really is pi? 3.1444 Penny Nom lui répond. 





The circumference of a 72 
20020814 

Linda pose la question : What is the circumference of a 72" diameter circle? Penny Nom lui répond. 





The area of a circle 
20020603 

Jessica pose la question : I am doing a maths assigment for university, which is aimed towrds primary school students(k6). I was wondering if you could give me some information as to how I could describe to students the rule for finding the area of circle, using a circle cut up into equal sectors (like a pizza). I know it has something to do with the fact that you can make these shapes into a parallelogram, but I am a bit uncertain as to how I can express this idea clearly and articulately to students. Penny Nom lui répond. 





Overlapping circles 
20020529 

Naman pose la question : There are two circles, big circle with radius R and small one with radius r. They intersect and overlap in such a way that the common area formed is 1/2 pi r^{ 2} (half the area of the small circle) If r=1, find the Radius of the big circle (R)? Harley Weston lui répond. 





3 radians subtends an arc of 27 meters 
20020522 

Kyle pose la question : In circle O, a central angle of 3 radians intercepts an arc of 27 meters. Find the number of meters in the length of the radius. Penny Nom lui répond. 





Chord length 
20020517 

Ashlie pose la question : How do you find the chord length of one section of a chord if you only have the diameter length and the other whole chord length. WV is the diameter and equals 16. XY is perpendicular to it, and equals 10. They intersect at pt. Z. I need to know what WZ equals. Please help! Penny Nom lui répond. 





A triangle in a circle of radius 6 
20020326 

Marko pose la question : In a circle of radius 6, a triangle PQR is drawn having QR = 8 and PQ = 10. Determine the length of PR Chris Fisher lui répond. 





The isosceles triangle of smallest area 
20020308 

Lettie pose la question : can you find the isosceles triangle of smallest area that circumscribes a circle of radius of one? Walter Whiteley lui répond. 





A circular wading pool 
20020304 

Patrick pose la question : The community of melfort is planning to build a circular wading pool in the park. The pool will cover an area of 1000m^{2}. The building committee has decided to put a 5m cement pad around it. How much additional area will the cement pad take up? Harley Weston lui répond. 





Two circles inscribed in a rectangle 
20020227 

Amina pose la question : Given a rectangle with dimensions L=6, H=5. Two circles are inscribed such that they touch each other(circles are adjacent to each other) and also their circumferences touch 2 sides of the rectangle. One of the circles has radius=4. Find the radius of the other circle. Penny Nom lui répond. 





The distance across a circle 
20020118 

Douglas pose la question : If you know how far around a circle is (say earth) 25000 miles how do you calculate the distance across? Penny Nom lui répond. 





An octagon inscribed in a circle 
20020110 

Kent pose la question : A circle of 30 in. diameter has an octagon (8 equal chords) inscribed in it. What is the length of each chord? Chris Fisher lui répond. 





Isoperimetric quotients 
20020102 

A student pose la question : I'm stuck on my GCSE Maths coursework, what do isoperimetric quotients measure? Penny Nom lui répond. 





A circle and triangle overlap 
20011109 

Tara pose la question : A circle and triangle overlap as shown.the area of the circle is three times the area of the triangle.If the common region is removed,then the area of the rest of the circle would be 14 sq cm more than the area of the rest of the triangle.How many sq cm are in the area of the complete triangle. Penny Nom lui répond. 





A circle and a triangle 
20011109 

Tasha pose la question : I have a circle that has an equalateral triangle inscribed in it. The tip of the triangle (B) is at the center of the circle with the other corners (A & C) extending to the sides of the circle. I need to know the equation to find the linear length of AC. I also need to find the cordial length of the circle from point C to A. Penny Nom lui répond. 





Squaring the circle 
20011023 

Margaret pose la question : I have the following question that I cannot answer on my own (I don't know where to begin): Is it possible construct a square whose area will equal the area of a given circle? Please Explain why or why not. Penny Nom lui répond. 





Dividing a circle 
20011017 

Ahmeen pose la question : I am having a hard time figuring out how a circle can be divided into 11 equal parts with only 4 cut allowed? My teacher gave this to us and I still can't cut my pie into eleven equal parts with only four cuts. Walter Whiteley lui répond. 





A circle and a triangle 
20011004 

Christina pose la question : The points (3,4), (9.2), and (3,2) define a circle and a triangle.  find the areas of the circle and the triangle. Find the difference between their areas.
 Find the length of a side of a square with the same area as the triangle.
 Find the length of a side of a Square with the same are as the circle.
Penny Nom lui répond. 





An egg shaped island 
20010922 

Karen pose la question : I am a civil engineering designer trying to design an egg shaped island. I want a 30' radius at the top and a 40' radius at the bottom and the longest length of the egg to be 125'. Is there standard geometry for an egg shape? I am not held to exact radii or the length given. Chris Fisher lui répond. 





Three chords 
20010628 

Paul pose la question : AE is a diameter of a circle and AC, CD and DE are chords of lengths 1, 2 and 3 respectively. (See the diagram.) Find the ridius of the circle. Harley Weston lui répond. 





Three tangents to a circle 
20010627 

Stephanie pose la question : The three lines PS, PT, and RQ are tangents to the circle. The points S, X, and T are the three points of tangency. Prove that the perimeter of triangle PQR is equal to 2PT. Chris Fisher lui répond. 





How many sides does a circle have? 
20010516 

Georganne pose la question : How many sides does a circle have? My son answered "infinate" on a test and was corrected. The school insists the answer is 0. Chris Fisher and Denis Hanson lui répond. 





Circles, ellipses, parabolas and hyperbolas 
20010509 

Colleen pose la question : How is an ellipse like a circle? In what way does an ellipse have a center? How is a hyperbola similar and different to an ellipse? How is a parabola similar a different to a circle ellipse and parabola? Pnny Nom lui répond. 





A geometry proof 
20010418 

Melissa pose la question : Extend the bisectors of angle A, angle B, and angle C of triangle ABC to meet the circumcircle at points X, Y, and Z respectively. Show that I is the orthocenter of triangle XYZ. Chris Fisher lui répond. 





The unit circle and trigonometry 
20010405 

Ashley pose la question : "My teacher wants us to find out what a unit circle is, which I found out, a circle with the radius of 1, but the problem is he wants us to show the relationship between the unit circle and the sine(30,45,60 degrees), cosine(30,45,60 degrees),and tangent ratios(30,45,60 degrees). I need help with this and my teacher will not help us out. Thanks very much ... Penny Nom lui répond. 





Arc of a sphere 
20010304 

Some students pose la question : My friends and i have a geometry project and we cannot seem to figure out how to find the arc of a sphere. Harley Weston lui répond. 





A quartercircle and two semicircles 
20001231 

Christopher pose la question : Inside the quartercircle are two semicircles with the same radius, (r). Which has a greater area, G or L? Penny Nom lui répond. 





Inscribing a circle in a rhombus 
20001116 

Jacky pose la question : A rhombus ABCD is drawn in which the diagonals are 12 and 20 units long. A circle is inscribed in the quadrilateral with the centre of the circle right on the intersection point of the 2 diagonals. The circumference of the circle touches all 4 sides of the rhombus. Is it possible to find the radius of the inscribed circle? If so, how and what is it? Chris Fisher lui répond. 





Overlapping a circle and a square 
20001028 

Jacky pose la question : A square with a dimension 20 by 20cm. and a quarter of the circle with the radius of 25cm (A quater of a circle is created by 2 cuts that are perpendicular bisectors of each other where the intersecting point is at the centre of the circle). With these 2 pieces, the 2 pieces are placed over each other in which the 90^{o} angle of the quarter circle matches with one of the right angles on the square. Now, calculate the overlapping area of the 2 figures. Chris Fisher and Harley Weston lui répond. 





A chord length 
20001017 

Al Paas pose la question : How to determine the length of a chord given the diameter of the circle and the maximum distance from the chord to The circle? Chris Fisher lui répond. 





Area of a circle 
20000803 

Larry pose la question : I know the formula is pi r squared. For a circle 4 inches in diameter, do I multiply pi (3.1416) by the radius (2") then square the answer to that ie: 3.1416 X 2 squared or do I square the radius (2 X 2") then multiply by pi (3.1416) ?? Penny Nom lui répond. 





The circumference of a circle 
20000730 

Not a student pose la question : An equalateral triangle is enclosed in a circle. The three corners touch the edges of the circle. One side of the triangle is 12. What is the circumference of the circle? Penny Nom lui répond. 





A semicircle and a triangle 
20000728 

Ben pose la question : A semicircle and an isosceles triangle ABC have the same base AB and the same area. The equal angles in the triangle are BAC and CAB. I have to find the value of each of these angles. Harley Weston lui répond. 





Parallel tangents 
20000630 

Ebony Indalecio pose la question : I need to prove the theroem: Tangents to a circle at the end points of a diameter are parallel. Walter Whiteley lui répond. 





Circumference = Area 
20000419 

Scot George pose la question : The area and circumference of a circle has the same measurement. Find the radius. Chris Fisher lui répond. 





An equilateral triangle in a circle 
20000311 

Michael Setlik pose la question : An equilateral triangle is drawn within a circle such that all three points of the triangle just touch the inside of the circle. Given the diameter of the cicle as six inches what is the length of the sides of the triangle? Harley Weston lui répond. 





Grazing area for a goat 
20000310 

Amy pose la question : A goat is tied in the middle of a side of a square building whose sides are 2 yards long. The rope is 4 yards long. What is the grazing area for the goat? Harley Weston lui répond. 





Area of a circle 
20000229 

Michelle Buboltz pose la question : My name is michelle and I just need to convert 25 ft across a circle into how many square feet. Penny Nom lui répond. 





The isoperimetric theorem 
20000224 

Raj Bobal pose la question : How can you prove Mathematically that the maximum area enclosed by a given length is a circle? Chris Fisher lui répond. 





A triangle and a circle 
20000223 

wendy pose la question : If a triangle of base 6 has the same area as a circle of radius 6, what is the altitude of the triangle? I am having trouble with altitude. Penny Nom lui répond. 





Filbert Family Circus 
20000204 

Sarah pose la question : As Clyde moves his broom around the circus ring, he thinks that he has finally found a job where he can make a clean sweep of things. Clyde is sweeping the ring where the lions perform in the Filbert Family Circus. The ring is 76 feet across and Clyde is using a broom 3 feet wide. He starts at the outside edge and works his way to the middle, making circles around the ring. After sweeping 3/4 of the ring, Clyde sees the lions coming with their trainer and scurries out of the ring. How many trips around the ring did he make? Penny Nom lui répond. 





A problem with a radius. 
20000201 

Howard B Davis pose la question : We start a Line that goes up 1 unit, then it goes to the Right for 5 units long, and then goes down 1 unit which is the end point. If we draw a circle that is tangent to both ends as well as the midpoint of the horizontal line: How do we find the radius of the arc; in Mathematics, with only this information? Chris Fisher lui répond. 





Arclength of a circle 
20000119 

Holly pose la question : What is the formoula for finding the arc length of a central angle of a circle?? Harley Weston lui répond. 





Area of a circle and an inequality 
19991030 

Adam Anderson pose la question : I have two problems. The first: prove that the area of a cirlce is pi times radius squared without using calculus. The second: show that ln(x) < x  1 for all x > 0. Harley Weston lui répond.






The circumference of a circle 
19991005 

Mara Frost pose la question : what is the formula to find the circumference of a circle, or if there is no formula, how do you find the circumference of a circle? Penny Nom lui répond. 





Rolling Circles 
19990912 

Craig Ellis pose la question : We have a circle of radius 3. inside the circle and tangent to the circle of radius 3 at one point is a circleof radius 1. The question is if we could roll the smaller circle around the inside of the larger circle how many revolutions would it take to get around to where we started. Chris Fisher and Walter Whiteley lui répond. 





Circles, cirmcuference and area 
19990516 

Stephen Ehrler pose la question : I would appreciate if you could please tell me if what I discovered here is something or my ignorance? I noticed that a circle with r radii has the folling characteristic. r = [2 * ( pi * r^{2} / pi * 2r)] The equation states that the ratio of a circles area over its circumfrence = 1/2 that of the circles radii. It works every time. Did you know this ? Is it some kind of therom and can it be used for any thing? I thought this was intresting and would appreciate any input you may have. Thank you. Chris Fisher lui répond. 





Radius of an arc 
19990422 

Rusty Riddleberger pose la question : I need to find the equation for finding the radius of an arc; I know the length of the arc (i.e the distance of the line connecting the two ends of the arc) and the height; (i.e the rise of the arc at its apex,) I had the formula years ago but it has lost me; this would be invaluable for work in new homes i.e. where we need to build an "arch" with a rise of 21" between two columns 11 feet apart Chris Fisher lui répond. 





Circles 
19990421 

Alex Elkins pose la question : How do you find the circumference of a circle if you only know the radius and the square feet or inches of the circle if the radius is 18 inches, If done in inches do you multiply by 12 to get the square feet? Jack Lesage and Harley Weston lui répond. 





Volume of oil in a tank 
19990417 

Lars Waldemarsson pose la question : My problem is to get an equation for the depth of the oil in a gastank formed like a cylinder. The cylinder is in a horizontal position and by a stick you will be able to get the depth of the oil in the tank. All I need is an exmaple which I can build on. By this equation you will be able to get the volume of the oil if you know the depth. Harley Weston lui répond. 





Dividing a Circle 
19990412 

Mike Kenedy pose la question : I am having trouble with a homework question for bonus marks. A Circle is continually divided by lines that do not intersect the center so that they produce the most pieces of circle. For example  1 line divides the circle into 2.
 2 into 4.
 3, however into 7.
 4 into11
 5 into 16
 6 into 22
 7 into 29
 8 into 37
 etc...
I am stumped and cannot figure out the equation, though I'm sure it involves squares. Can you help? Penny Nom lui répond. 





Circumference and Area 
19990216 

Natalie pose la question : finding the circumference of a circle? formula finding the area of a parallelogram? formula
Penny Nom lui répond. 





Dig digs in the garden 
19990211 

Katherine Shaw pose la question : A circular garden has an a radius of 8m. Dig, the dog, is tied up to a fence that runs round the outside of the garden. Dig was able to dig up all the garden, apart from an area of 64 square metres, which he couldn't reach. How long was his lead? Chris Fisher and Harley Weston lui répond. 





Two Chords 
19980929 

Jennifer Cane pose la question : Question: two parallel chords of a circle, AB and CD, have lengths of 10 cm and 17 cm respectively. The diameter of the circle is 21 cm. Find the shortest distance between the chords. Harley Weston lui répond. 





The area and the circumference of a circle. 
19980827 

Jason Wright pose la question : I was looking at the relationship of the area of a circle and the circumference when I realized that 2*pi*r is the derivative of pi*r^2. I was wondering if there is any connective deep dark meaning as to why this appears to be related. Thanks for any help you can give me! Walter Whiteley lui répond. 





Two Inscribed Trapezoids 
19980127 

James pose la question : A hexagon inscribed in a circle has three consecutive sides each of length 3 and three consecutive sides each of length 5. The chord of the circle that divides the hexagon into two trapezoids, one with three sides each of length 3 and the other with three sides each of length 5, has length equal to m/n, where m and n are relatively prime positive integers. Find m+n. Haragauri Gupta lui répond. 





A geometry problem 
19971120 

Herman pose la question : When produced, two equal chords AB and CD of a circle meet at P in an angle of 24 degrees. If H is the midpoint of AB and K is the midpoint of CD, calculate the size of angle HKD. Penny Nom lui répond. 





Pi 
19971031 

Ryan McKinnon pose la question : What Is Pi? Chris Fisher lui répond. 





A Geometry Problem 
19970918 

Rebecca Henry pose la question : A circle is centered at the vertex of the right angle of an isosceles triangle. The cirlce passes through both trisection points of the hypotenuse of the triangle. If the length of a radius of the circle is 10, find the area of the triangle. Chris Fisher Harley Weston lui répond. 





The Length of a Chord. 
19970726 

Nathan Arthur pose la question : Picture a 9 inch diameter circle. Inside that circle is a 6 inch diameter circle tangent to it. Then, tangent to both circles is a 3 inch diameter circle. So there are three circles, two smaller ones inside a big one, all of them just touching but not overlapping. Now picture a chord on the 9 inch circle that is created by making a line that is tangent to both the 6 and the 3 inch circles and extending it to the edge of the 9 inch circle. I need the length of that cord. Chris Fisher lui répond. 





The angle between two tangents. 
19970609 

Felix Ho pose la question : Two tangents are drawn from the origin to the circle (x)(x)+(y)(y)4x6y+9=0. If the angle between the tangents is m, fine the value of tan(m). P.S. (x)(x)=square x Harley Weston lui répond. 





Area Between Two Sectors 
19970302 

Rebecca Henry pose la question : Points A,B,C,D,E,F are equally spaced on a unit circle. Arc CGE has a center A. Find the number of square units of area in the shaded region. Walter Whiteley lui répond. 





Some Circle Questions. 
19970225 

Staci Vawser pose la question : A circle with a radius of 10m is drawn. A chord is drawn across the circle. How is the area that is formed between the chord and the arc calculated? Harley Weston lui répond. 





Circular Permutations 
19970205 

Ed Varjassy pose la question : I have an understanding of simple problems involving circular permutations but do not understand them when they start to have restrictions. Is there any advice you can give for these more complicated permutations. Penny Nom lui répond. 





Common Area of two sectors. 
19961106 

Lynda Mow pose la question : How do I find the area common to two intersecting circles of radii 8 ft and 10 ft if their common chord is 10 ft long? Penny Nom lui répond. 





A tangent to a circle is perpendicular to the radius at the point of contact. 
19961022 

Rita Leung pose la question : I wonder if there is any proof for this theorem  A tangent to a circle is perpendicular to the radius at the point of contact. If there is any proof for that, can you tell me please? Chris Fisher and Harley Weston lui répond. 





Why is a circle divided into 360 degrees? 
19960930 

Kurtis Kredo pose la question : I was recently wondering why a circle has been divided in to 360 degrees. When I asked my physics teacher he could not think of an answer. His guess is that it probably has to do with people long ago using the base 6 number system. I have a small inkling that it has to do with easy conversion or usage with radians or grads. Chris Fisher lui répond. 





Area of an annulus 
19960404 

Ryan Levering pose la question : What is the area of this annulus? Penny Nom lui répond. 

