







Rates, percentages and units 
20141230 

Kenneth pose la question : Hello:
If percentages have no units, why are some percentages called rates, as in interest rate, or
perhaps a tax rate of 7% as an example? A rate has units of different quantities.
I thank you for your reply. Robert Dawson 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. 





Trig functions for angles not between 0 and 90 degrees 
20070716 

Tim pose la question : My question: Why is the value of a trigonometric function, the same, for an angle over 90 degrees and its reference angle?
How are the angle and its reference related? Do they both form a triangle that has equal sides? Penny Nom lui répond. 





Inclusive definitions 
20051214 

Layla pose la question :
recently the solvable quandary of 5+5+5=550 came up (the question says that you have to put 1 straight line somewhere in the equation to make it true with out turning the "=" into a "not=" sign).
So two answers were put forward:
545+5=550 (the use of a line converting a + into a 4)
AND
5+5+5(less than or equal to)550
There is currently an argument about the second solution. The disagreement is about whether this sign can be used. One person is arguing that the "less than or equal to" sign defines that the number on the left is in the range 550 and below. The other is saying that since the number (which is clearly defined with no variables) can never equal 550, then the "less than or equal to" sign cannot be used in this case.
Which one is the correct definition?
Walter Whiteley lui répond. 





Is a square a rectangle? 
20041121 

Carol pose la question : I am a teacher. In an FCAT sixth grade review test, there was a question to the students to draw a square and then they referred to it as a rectangle.
What is the definition that makes a rectangle a square that can be taught to the students without confusing them. Walter Whiteley 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. 





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. 





The vertex of a cone 
20030327 

Holly pose la question : I read your response to Callie about whether a cone has a vertex or not. Is it ONLY a vertex if both halves of the cone are together or can one half of the illustration have a vertex? Walter Whiteley lui répond. 





Can a square be a rhombus? 
20030304 

Beth pose la question : Can a square be a rhombus? Some sources say yes, some say no. Some sources define a rhombus as a quadrilateral and parallelogram with equal sides, but without right angles. Some sources say a square is a special case of a rhombus. Clarity, please! Walter Whiteley lui répond. 





Pyramids and prisms 
20000118 

Tyler pose la question : What's the definition of a Triangular Prism and a Triangular pyramid. Penny Nom lui répond. 

