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3 votes
What is the radius of the circle whose area is numerically 5 times greater than its circumference?

A) 5
B) 10
C) 4 pi
D) 2 pi
E) pi

The answer is 10, why?

1 Answer

1 vote
Pi*r^2 = 5(2*pi*r)
pi*r^2 = 10*Pi*r
divide the equation by pi
r^2=10*r
divide the equation by R
r = 10
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