Consider the following.

Question

(a) Set up an integral for the volume a solid torus (the donut-shaped solid shown in the figure) with radii br and aR. (Let a = 8 and b = 2.)




dy
(b) By interpreting the integral as an area, find the volume V of the torus.
V =

Answer 1

There are several ways to do this. I'd google the topic. You might start here:

http://whistleralley.com/torus/torus.htm