i am pretty sure the answer is <em><u>C. 13</u></em>
I believe it would be answer A. because it says he has a total of 180 pieces and all those numbers on the right add up to be 180.
Multiply by the denominator on both sides
ANSWER:

STEP-BY-STEP EXPLANATION:
The center of the circle would be the mean value between the end points, and we can calculate it like this: