From Calculus 1:

A ball of radius 13 has a round hole of radius 7 drilled through its center. Find the volume of the resulting solid.

Okay, I have no idea what I am doing wrong here:

General plan is to find the volume of the ball and then subtract the volume of the part drilled out.

The volume of the ball:

V = 4/3pi(13^3) = 9202.77208

volume of the part drilled:

V = Hpi(7^2) = 26 * pi * 49 = 4002.389041

So I get a final answer of about :

5200.38

But it's the wrong answer. Help??