This circle has a circumference of 56. What is the radius of the circle?

Answer 1

C = pi * r^2
56 = 3.14 * r^2
56/3.14 = r^2
17.834394 = r^2
4.223 = r

Answer 2

The problem involves circumference, not area.

C = 2 pi r
56 = 2 pi r
28/pi = r = 8.91