Question

The formula for the circumference of a circle is c=pi r where r is the radius and c is the circumference. The equation solved for r is r=c/2pi. Find the radius of a circle that has a circumference of 16pi.

A. r=4
B. r=8
C. r=12
D. r=16

Answer 1

B. r=8

Explanation:

r=c/2pi

We are given c = 16 pi

r = 16pi / 2pi

The pi on the top and bottom cancel

r = 16/2

r =8