Question

If the diameter of the circle above is 18 in, what is the circumference of the circle?

Answer 1

18π in

Explanation:

The formula for the circumference of a circle whose diameter, d, is given is

C = πd.

In this case the diameter is 18 inches. Thus, the circumference is

C = π(18 in) = 18π in

Answer 2

Diameter = 18, so radius = 9
Circumference = 2 x pi x 9
= 56.55