A semicircle has a radius of 9. What is the approximate perimeter of the semicircle? Choose the correct choice:
A) 16
B) 25
C) 33
D) 46
E) 58
The perimeter of a circle is 2*pi*r.   The perimeter of a semicircle is 2*pi*r/2 + 2r = pi*r + 2r   The perimeter is pi*9 + 2*9 which is about 46.   The answer is 46.
<result>D</result>
A semicircle has a radius of 9. What is the approximate perimeter of the semicircle?