Answer:
D. pi
Step-by-step explanation:
Circumference of a circle = 
Diameter = d
Therefore, ratio of circumference of a circle to its diameter would be:

=> (d cancels d)
Therefore, the ratio of the circumference of a circle to its diameter is 
Since the exponent is negative, you move the decimal (2.0) to the left two spots leaving you with .02
Each exterior angle = 360 / 40 = 9 degrees. So each interior angle = 180 - 9
= 171 degrees.