The upper right-hand corner of a piece of paper, 12 in. by 8 in. is folded over to the bottom edge. How would you fold it so as to minimize the length of the fold? In other words, how would you choose x to minimize y?
I know I need to use similar triangles and the Pythagorean Theorem (a^2+b^2=c^2) but I'm not sure of how to start the problem