Help pls! Two Boys are building a skateboard ramp. They want the ramp to be 3 feet tall and 5 feet long. One of them thinks that they can use a piece of plywood that is 4 feet long to cover the top of the frame. This is one of theirs work.

a2 + b2 = c2
32 + b2 = 52
9 + b2 = 25
b2 = 16
b = 16−−√
b = 4

Why is his reasoning incorrect? Explain.

How long does the piece of plywood have to be to cover the top of the frame of the skateboard ramp? Round your answer to the nearest tenth of a foot. Show your work.

Another boys parents bought a 10 foot piece of plywood for him and his friend to use to cover the top of the frame. Draw and label a ramp they could create. Justify your work using the Pythagorean Theorem.
Draw