Question

What is the circumference, in inches, of a circle with an area of 81π square inches?

Select one:
A. 6π
B. 9π
C. 12π
D. 15π
E. 18π

Answer 1

If area is 81pi then 81pi=pir^2. Divide both sides by pi and we are left with r^2=81 take the square root of both sides to find the radius is 9 then plug that into the equation for circumference(2pir) so 2pi(9)=18 pi so the answer is E 18pi