The formula to calculate the Annular Ring (AR) is:
\[ AR = 2 \pi (R + r) \]
Where:
Let's say the outer radius (R) is 10 inches and the inner radius (r) is 5 inches. Using the formula:
\[ AR = 2 \pi (10 + 5) \]
We get:
\[ AR = 2 \pi \times 15 = 94.25 \text{ inches} \]
So, the annular ring is approximately 94.25 inches.