PreAlgebra
posted by Joy .
I don't really know how to find what the lenght of the hypotenuse is.

If the length of leg #1 is 5, and the length of leg#2 is 12. What is the hypotenuse?

Use the pythagorean theorem. c^2 = a^2 + b^2. c is the hypotenuse and a and b are the legs. So in this case, you'll be solving for c.