Enter the outer radius (in) and the inner radius (in) into the Annular Ring Calculator. The calculator will evaluate the Annular Ring.

## Annular Ring Formula

The following two example problems outline the steps and information needed to calculate the Annular Ring.

**AR = 2*pi*(R+r)**

Variables:

- AR is the Annular Ring (in)
- R is the outer radius (in)
- r is the inner radius (in)

## How to Calculate Annular Ring?

The following steps outline how to calculate the Annular Ring.

- First, determine the outer radius (in).
- Next, determine the inner radius (in).
- Next, gather the formula from above = AR = 2*pi*(R+r).
- Finally, calculate the Annular Ring.
- After inserting the variables and calculating the result, check your answer with the calculator above.

**Example Problem : **

Use the following variables as an example problem to test your knowledge.

outer radius (in) = 5

inner radius (in) = 3

AR = 2*pi*(R+r)** **= ?