What is the circumference of a circle whose area is 100 pi?

The formula for finding the area of a circle is pi times the radius squared. Let's find the radius of the circle. 100 pi/ pi= 100. Squarerooted, the radius is 10. The formula for finding the circumference of a circle is 2 times pi times the radius. So, plug in: 2 times pi times 10 equals 20 pi! Your final answer: 20 pi (or, if you use decimals, approximately 62.8)