







The difference between the ares of two rectangles 
20160609 

From Ingrid: I am trying to help my son with an area question.
I have the answer, from the solutions, but I cannot figure out how to teach him.
Question:
Two rectangles have lengths 13cm and 19cm respectively.
Their total area is 376cm squared.
If both their widths are whole numbers, what is the difference in their areas?
I know that this is solvable once I determine the widths of the rectangles ,
but how do I go about finding that?
Thanks for your help Answered by Chris Fisher and Harley Weston. 





The sum of the angles of a triangle 
20160224 

From Sophia: Does every triangle add up to 180 degrees? (Such as a unique triangle) Answered by Penny Nom. 





Euclid's Parallel Postulate 
20130820 

From Justin: Hello there,
I was wondering is Euclid's Fifth Parallel Postulate of parallel lines never intersecting, undecidable or essentially undecidable?
Thank you so much for any help you can provide! Answered by Robert Dawson. 





Express the HCF of 1232 and 573 as 1232x + 573y = 1 
20090222 

From Anonymous: Express the HCF of 1232and 573 as 1232x + 573y = 1. Answered by Victoria West. 





Greatest common divisor 
20070314 

From Marie: How do I prove this?
Let h be the greatest common divisor of the positive integers a and b.
Show that there exist integers p and q (not necessarily positive) such that
pa + qb = h.
Thanks Answered by Penny Nom. 





Show that 3k+2 and 5k+3 are relatively prime 
20070115 

From Andrea: show that if k is a positive integer, then 3k+2 and 5k+3 are relatively prime Answered by Penny Nom. 





How many children were there? 
20060514 

From Geecee: At a local village gala, the entire population turned up, 500 people. The event raised £3,000. Tickets were priced as follows: £7.48 men, £7.12 women and £0.45 children.
How many children were there? Answered by Stephen La Rocque. 





Absolute Value vs. Standard Deviation ? 
20060424 

From Sonia: Why we don't just take the average of the absolute value of difference scores (use the mean deviation) to describe variability instead of calculating the standard deviation? Answered by Claude Tardif. 





Noneuclidean geometry 
20031208 

From Geoffrey: How can you use noneuclidean geometry to navigate on a sphere? What geometers did work in this area? Answered by Chris Fisher. 





NonEuclidean geometry 
20031203 

From Geoffrey: What are the applications of NonEuclidean geometry (especially hyperbolic and spherical)? Answered by Walter Whiteley. 





The Euclidean Algorithm 
20020131 

From Murray: Can you please explain to me why the euclidean algorithm works? Answered by Penny Nom. 





Reduce 79,537/3,623,420 
20011213 

From Eliana: How do you reduce 79,537/3,623,420. Answered by Claude Tardif. 





Euclidean distance 
20000906 

From Velma ZahirovicHerbert: If d(x,y) is euclidean distance between x and y Prove that d(x,y)>=0 if d(x,y)=0 than x=y and d(x,y)=d(y,x) Answered by Paul Betts. 





Euclidean Math puzzle 
20000124 

From Margaret Matthews:
(Check out this website: Simeon's Triangle Puzzle ) I have tried to figure out how this could be, because everything I know about it tells me it can't be. However, I can't seem to make it NOT work. Two right angle triangles. They are each cut up into four identical pieces. In the first, all the pieces fit together so that there are NO empty spaces; in the second, presumed to be identical in size to the first, the pieces are slightly rearranged, and now, there IS a space in the triangle. Answered by Patrick Maidorn and Claude Tardif. 





NonEuclidean Geometry 
19990210 

From Robert Smith: Is noneuclidean geometry necessary for the college bound student? I have students that are inerested in teaching math one day. My school is restricted to Euclidean Geometry. Answered by Walter Whiteley and Jack LeSage. 

