Approximately how many cubic feet of water are needed to fill a circular swimming pool that is 40 feet across and 7 feet deep? Select the correct option:
A) 700
B) 1500
C) 3000
D) 5000
E) 9000
Answer Should be E.   V= \pir^2h= \pi*20^2*7= approximately 9000
<result>E</result>
Approximately how many cubic feet of water are needed to fill a circular swimming pool that is 40 feet across and 7 feet deep?