Question

If circumference and the area of a circle are numerically equal, find the diameter of the circle.

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Answer 1

d = 4

Explanation:

C = 2*pi r or C = pi * d

Area = pi *r^2= pi (d/2)^2 = pi * d^2 /4

So if they are numerically equal, you get

pi * d = pi * d^2 / 4 Divide both sides by pi

d = d^2 / 4 Multiply both sides by 4

4*d = d^2 Divide both sides by d

4 = d