Manhattan Prep Geo Guide - #1 p. 41

[Alexander]

Hi -

- I realized the ratios in A & B weren't exact values and were ratios. So I understand why in the explanation where the 'x' comes from ( 4:3 = 4x/3x).

- I don't understand the explanation for the diagonal and why there is an "x^2" term for it. The problem tells us an actual value of 25 inches, its not a ratio.

Thanks,
Alexander

[tommywallach]

Hey Alexander,

Not totally sure where the confusion is, but let me know if this helps. We define one side as 4x. We define another side as 3x.

So (4x)^2 + (3x)^2 = 25^2

That's all they do in the back of the book, but when they square root both sides, they simplify the LEFT side first. That side comes out to 5x, and the left side is 25.

-t