area = PI x R^2
66 = 3.14 x R^2
R^2 = 66/3.14 =21.019
r = sqrt(21.019) = 4.58466 meters
check:
Area = 3.14 x 4.58466^2 = 66.033
Radius = 4.58466 meters
Round answer as needed.... you didn't say how the answer should be rounded
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