# Area of a Circular Ring

In this section we will  tell you regarding the area of a circular ring :

The area of a ring bounded by two concentric circle of radii R and r (such that R > r)

= Outer circle's area – Inner circle's area

= aR${}^{2}$ - ar${}^{2}$

= a(R${}^{2}$ - r${}^{2}$)

= a(R + r) (R - r)

Hence, the area of a circular ring = a(R + r) (R - r), we know that R and r are the radii of the  bigger circle and the smallest circle respectively.