If the area of a circle is 64pi square feet, find its circumference.  Choose the most appropriate option
A) 65 pi feet  B) 43 pi feet  C) 42 pi feet  D) 18 pi feet  E) 16 pi feet
The area is given by pi * r * r. Hence   pi * r *r = 64 pi   r *r = 64 ; hence r = 8 feet   The circumference is given by   2 *pi *r = 2 * pi * 8 = 16 pi feet   correct answer 16 pi feet
<result>E</result>
If the area of a circle is 64pi square feet, find its circumference.