# Surface Area of Revolution

1. Dec 21, 2009

### ƒ(x)

I know that the surface area of a revolution is equal to the integral from a to b of 2pi times the radius time the arc length. But, why isn't it just the integral from a to b of the circumference?

2. Dec 21, 2009

### ƒ(x)

Nevermind, I found the answer in a previous post.