Okay, so first you need to know the a^2+b^2=c^2 formula which allows you to find the lengths if only two are given. Since you already have all three lengths, you plug them in for a, b and c. In this case it would be 6^2+8^2=9^2 because you plug in the longest length for c. Your answer would be 100=81 which Is false, so not a right trainge.
