Question

The area of a circle is 9π ft What is the circumference, in feet? Express your answer in terms of \piπ. (pi)

Answer 1

6×pi ft

Explanation:

the area of a circle is

pi × r²

with r being the radius of the circle.

so,

9×pi = r² × pi

9 = r²

r = 3 ft

the circumference of a circle is

2×pi× r

that means in our case it is

2×pi×3 = 6×pi ft