A circle has an area of 81π in2. Which of the following is the circumference of the circle in terms of pi ( π)?
A. 4.5 π in
B. 14 π in
C. 18 π in
D. 9 π in
we need to find the circumference of the circle from the given area.
The first step is to find the radius of the circle using the given area. Let r be the radius of the circle, then:
Substituting the value of area in the above equation becomes
Dividing both sides by pi and taking square root on both sides yields
Now, we know the radius of circle to be 9 in, the circumference of the circle becomes,
in.
Therefore, the Correct Answer is C.