Question 818352: Find the diameter of the circle that has a circumference equal to its area.
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Answer by TimothyLamb(4379)   (Show Source):
You can put this solution on YOUR website! a = pi*r*r = r*pi*r
c = 2*pi*r
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first method:
for a to equal c the value of r would have to be 2:
a = r*pi*r = 2*pi*r = c
a = 2*pi*2 = 2*pi*2 = c
r = 2
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second method:
a = pi(rr)
c = 2pi(r)
pi(rr) = 2pi(r)
pi(rr)/pi = 2pi(r)/pi
rr = 2r
rr/r = 2r/r
r = 2
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