







Running in opposite directions around a circular track 
20200511 

Alessandra pose la question : 2. Alan and Brian are two runners. Alan runs at 6.6 m/s and Brian runs at 8.4 m/s. They start from
the same place on a circular 400 m track and run in opposite directions round and round the
track.
(a) How far has Brian run when they pass each other for the first time?
(b) After they pass each other for the second time, how much further does Brian need to run
in order to complete two laps (800 m)? Penny Nom lui répond. 





A rectangular prism with rounded corners 
20180425 

Jackie pose la question : Rectangular prism that is 40 by 20 with rounded corners with a radius of 2.5.
What would the surface area be? Penny Nom lui répond. 





A square peg in a round hole 
20170529 

bill pose la question : bill wants to put a 2 foot square peg into a round hole What must be the circumference of the hole? Penny Nom lui répond. 





Why does 10x10x10 give 1,000.0000000000001? 
20170412 

Randolph pose la question : Hi, On your calculator I found that a box 10 by 10 by 10 inches has a volume of 1,000.0000000000001 cubic inches. Can you explain the numeral 1 thirteen places past the decimal? Thanks, Randy 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. 





Prove the earth is round 
20160130 

Kevin pose la question : Working on a project for a science fair.
To prove the earth is round without the ability to get way above the surface.
How could we set up and experiment to see the curve.
My thought is using a telescope at the beach?
Form what we see so far the curve is 8 inches per mile?
So thought is set up a telescope and a target 1 mile away? Robert Dawson and Chris Fisher lui répond. 





The surface area of a round bar 
20150606 

chirag pose la question : Please tell me the formula for finding round bar surface in square inches/ mm 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. 





6 golfers in threesomes over 7 rounds 
20130924 

David pose la question : I have 6 golfers, (2 threesomes) who will be playing 7 rounds of golf. What is the best way to pair the 6 players so they play with as many different players over the 7 rounds? Victoria West lui répond. 





8 golfers, 3 rounds 
20130415 

justin pose la question : I have 8 golfers going on a trip. We have 3 rounds to play.
We would like to play with everyone (with or against.) Is this
possible? If so could you send me the formula please and thank you! Robert Dawson 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. 





The volume of a round tube 
20120207 

I.C pose la question : I need to find out how long a 10" round tube needs to be in order for there to be .95 cubic feet of air space Harley Weston lui répond. 





Rounding 
20111214 

seth pose la question : A decimal number rounded changed to 23.7 after it was rounded.
Give a decimal number that is less than 23.7 and another that is greater than 23.7 that each round to 23.7.
Explain to what place each number was rounded. Penny Nom lui répond. 





16 golfers and 8 rounds 
20110526 

Gerry pose la question : 16 golfers and 8 rounds. To have each player play with as many others as possible. Victoria West lui répond. 





The nearest one and a half and the nearest inch 
20110202 

Miranda pose la question : REASON:sarah gave the same answer when asked to round 4 seven eighth inches to the nearest one and a half and the nearest inch. explain why sarah is correct? Penny Nom lui répond. 





A rectangle with rounded corners 
20101021 

Connie pose la question : How do you find surface area if the rectangle is 100ft. by 200ft. with quarter circles in the corners with a radius of 20ft. ? Penny Nom lui répond. 





An 18ft round pool 
20100719 

christine pose la question : will an 18ft round pool fit on a 12x16 ft rectangular cement slab? Tyler Wood 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. 





15 golfers 3 rounds fivesomes 
20091223 

Dewey pose la question : I have 15 golfers playing 3 rounds of golf. We will be playing in fivesomes. Any formula that has everyone playing with a different person each round?
Thank you.
Dewey Robert Dawson lui répond. 





Greatest Number in Rounding Off 
20090625 

paucath pose la question : what is the greatest number that can be rounded of to 4000 Janice Cotcher lui répond. 





A 4 digit number 
20090412 

kaylin pose la question : When a 4 digit rounded to the nearest thousand,it rounds up to 3000. the hundred digit is less than 6. the digits in the ten and ones place add to a sum of 8 and they are the same . what is the number Robert Dawson and Penny Nom lui répond. 





A three digit number 
20090120 

marcha pose la question : when this three digit number is rounded to the nearest ten, the sum of its digits
is 16 the hundreds digit of this number is 8 and the ones digit is 5, what is the number? Robert Dawson lui répond. 





Compatible numbers 
20081002 

jeff pose la question : what exactly are compatible numbers,
math problem is:
Estimate the total weight of 2 boxes that weigh 9.4 pounds and 62,6 pounds
using rounding and compatible numbers. Which estimate is closer to the actual weight and why? Harley Weston lui répond. 





Rectangular cards on a round table 
20080611 

Susan pose la question : How many 4" X 3.5" wide escort cards will fit on a 48" diameter table. These are for my daughters wedding. I have already added the extra spacing between the cards into the size of the cards.Thanks for your help Janice Cotcher and Harley Weston lui répond. 





Rounding 
20080509 

wendell pose la question : write a three digit number that when rounded to the nearest ten and the nearest hundred, the answers are the same Penny Nom lui répond. 





Rounding 
20071105 

Charles pose la question : I have been asked to explain why rounding to 3 decimal places
has become the adopted industry standard in mathematics for
showing measurement calculations. I understand that it makes
sense to round financial calculations to 2 d.p. because then it's
rounded to the nearest penny (or cent) but why would the standard
in measurement be 3? Stephen La Rocque lui répond. 





Dirt in a sloped round hole 
20070803 

Ken pose la question : How much dirt do I need to fill a ground hole 20 ft in dia. with a sloping floor that has a ht. of 5" on one side and 12" on the other side? Stephen La Rocque lui répond. 





The size of a lot 
20070613 

Larry pose la question : This is driving me crazy, I know i learned this in college but that was so many years ago haha. I am trying to determine how many acres
my property is. Unfortunately everywhere i look is like another language to me when seeing these formulas. My property is square shaped
so starting from one side and just working around the dimensions are: 114 feet x 95.88 feet x 100 feet x 91.91 feet. Penny Nom lui répond. 





Percentage increase and decrease 
20070613 

Anna pose la question : I just want to if the following formula is used for the computation of a PERCENTAGE DECREASE:
Old Value  New Value/ Old Value x 100%
My immediate superior is under the impression that the said formula works ONLY for the computation of a percentage INCREASE. He believes that the formula for a percentage DECREASE:
Old Value  New Value/ NEW Value x 100%
On this score, I want to know the correct formula for the computation of percentage decrease. Thank you so much.
Penny Nom lui répond. 





A 5 digit key 
20070531 

Michael pose la question : I have a 5 digit key pad lock on my truck.
I want to print out all of the combinations to try.
pad one=0 pad two =1 pad three=2 pad four=3 pad five =4.
can you help me find and print all combinations? Harley Weston lui répond. 





Water tank volume 
20070529 

Cecelia pose la question : I HAVE A SEMI CIRCULAR TANK AGAINST A WALL MEASURING 6'10" ACROSS THE WIDEST PART AND 3' FROM THE WALL TO THE FRONT OF THE TANK. THE DEPTH IS 14". PLEASE HELP ME TO CALCULATE THE VOLUME OF WATER IN THE TANK. Stephen La Rocque lui répond. 





Rounding off 
20070415 

deepak pose la question : find the smallest and the greatest numbers which when rounded off to the nearest thousand, become 6000. Stephen La Rocque lui répond. 





Angular speed 
20061004 

Jack pose la question : A horse on a merrygoround is 7m from the center and travels at a speed of 10km/h. What is its angular speed? Stephen La Rocque lui répond. 





Estimating products by rounding 
20060924 

Ann pose la question : my son is in the fifth grade and they are doing estimate products rounding both factors, he knows how to round off a decimal, but he is having a problem doing a decimal and a whole number for example 5.96x3=? He knows the 5.96 round off to 6. but what does the 3 round off to? Penny Nom lui répond. 





An aircraft going from city A to city B 
20060510 

Preston pose la question : An aircraft going from city A to city B on a bearing of S69 degrees East is traveling at a speed of 430 mph. The wind is blowing out of the north to south at a speed of 25 mph. Find the ground speed and the plane's true bearing. Stephen La Rocque lui répond. 





Round to the nearest tenth 
20060506 

Lisa pose la question : how to round a decimal fraction to the nearest tenth Penny Nom lui répond. 





How do you round off 89,100? 
20060419 

Jeannie pose la question : My home work says to round each number to the place of the underlined digit. It has 89,100. The underlined number is 9. What do I do? Stephen La Rocque lui répond. 





Find the ground speed and the planes true heading. 
20060205 

Jimmie pose la question : An aircraft going from city A to city B on a bearing of S69E (degrees) is traveling at a speed of 430 mph. The wind is blowing out of the north to south at a speed of 25 mph. Find the ground speed and the planes true heading. Penny Nom lui répond. 





how do i round up 9.6 to the nears ones 
20050809 

Carlos pose la question : how do i round up 9.6 to the nears ones Penny Nom lui répond. 





Round to hundredths 
20021119 

Brittany pose la question : Can u tell me how to do a problem like this:
35 divded by 4.8= Round to hundreths. Penny Nom lui répond. 





Rounding 27.27 
20021103 

A parent pose la question : If you have a problem 27.27 and you need to round to the first 7 the answer would be 27 Would 27.0 be acceptable as well or is it completely wrong. Penny Nom lui répond. 





Multiplication of fractions 
20010108 

Angela pose la question : Questions:
1. represent multiplication of fractions via an area model 2. describe why, not just how, to round decimals Penny Nom lui répond. 





Rounding 
20000914 

MaryAnn pose la question : How many whole numbers rounded to the hundreds place, round to 400? Can you also explain why? Penny Nom lui répond. 





Rounding 
20000415 

Tawana Brown pose la question : I was uncertain as to whether a number such as 85.25 rounding to the nearest tenth would be 85.3 or 85.2. I thought I had heard somewhere that if 5 is the last number that you don't round up. But I have also heard that anything 5 and above you do round up. It's been awhile since I've done rounding, so I need a refresher course. Walter Whiteley and Harley Weston lui répond. 





Spreading a rumor 
19990913 

Bornstar14 pose la question : There is someone who wants to spread a rumor within 7 days to 250,000,000 people. he wants to know how many people he should tell on the first day (assuming the rumor is passed by everyone who was told to the same amount of people) so that everyone knows on the 7th day. What I did is the 7th root of 250,000,000. this answer is not possible unless rounded. is it okay for the number to be approximate? Penny Nom lui répond. 





Intersecting Lines. 
19980210 

Erik Heppler pose la question : My typewriter frequently makes mistakes. Suppose I gave you the following system of equations to solve: 35.26X + 14.95Y = 28.35 187.3X + 79.43Y = 83.29 When I looked back, I realized that I meant to use 14.96 as the "Y" coefficient in the first equation instead of 14.95. Solving the system using 14.95 and then solving another system using 14.96 with all other values the same both times results in the intersection points (1776, 4186) and (770, 1816) respectively. How can that be? Penny nom lui répond. 

