Answer: 18π cm
Explanation:
The circumference of a circle is equal to 2πr, with r being equal to the radius. The radius of a circle is defined as the length from any point on the circle to the middle. We are given the value of the radius as defined by the line that goes from the outer edge to the middle. The radius equals 9, which we can plug into the equation.
C= 2πr
C = 2π(9)
C = 18π cm
I hope this helps!