SOLUTION: If the area of the circle is 625pi square km, what is the diameter of the circle?

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Question 830494: If the area of the circle is 625pi square km, what is the diameter of the circle?
Answer by LinnW(1048) About Me  (Show Source):
You can put this solution on YOUR website!
area+=+%28pi%29r%5E2
625+=+%28pi%29r%5E2
divide by %28pi%29
625%2F%28pi%29+=+r%5E2
take square root of each side
sqrt%28625%2F%28pi%29%29=r
since diameter = 2 times radius
d=2sqrt%28625%2F%28pi%29%29
d=2%2A25sqrt%281%2F%28pi%29%29
d=50sqrt%281%2F%28pi%29%29 = 28.21