The region between two coplanar concentric circles.

### Formula

The area *A* of an annulus, where *R* and *r *is the radius of the small circle, is given by \(A=pi (R^{2}-r^{2})\)

The region between two coplanar concentric circles.

The area *A* of an annulus, where *R* and *r *is the radius of the small circle, is given by \(A=pi (R^{2}-r^{2})\)