# pythagorus

1. ### Proving the converse of Pythagorus

Prove that if a triangle has sides of lengths a, b and c, such that a2 + b2 = c2 then the triangleis right angled. The only thing i was thinking is cosing law. so a2 + b2 -2abcos(x) = c2 and so -2abcos(x)=0 therefore x=90degrees Is there a more elegant way to prove this?
2. ### pythagorus theorem proof

What is the proof originally given by Pythagorus? Help me please. I took a right angled triangle and then on each side I marked a square. After that, I do not know how to proceed? Any hint or clue please?
3. ### Take a WHIZ at this QUIZ!

hey, i've attached a picture. the following questions refer to it. 1. show that DA/XB=AX/BY=XD/YX 2. In a version of this diagram, DX=429 and DY=845. find the lenght and width of the rectangle ABCD cheers!
4. ### modified pythagorus theorem!

Hello, I need a little help in figuring this weird problem... --we know that (2+3)^2 is not equal to 2^2 and 3^2... however... (2+3)^2 = (2+1)^2 + (3+1)^2! so determine, all values for m and n such that--- (m+n)^2 = (m+1)^2 + (n+1)^2 Thanks!