Answer:
9 pi
Step-by-step explanation:
First find the circumference of the circle
C =2 * pi *r
C = 2 * pi *9
C = 18 pi
This is a semicircle which is 1/2 of a circle
Take 1/2 of the circumference
1/2 C = 1/2 ( 18 pi)
1/2 C = 9 pi
