SOLUTION: If the diameter of a circle is double the diameter of a second circle, what is the ratio of area of the first circle to the area of the second?

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Question 847348: If the diameter of a circle is double the diameter of a second circle, what is the ratio of area of the first circle to the area of the second?
Answer by fcabanski(1391) About Me  (Show Source):
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If the diameter of circle A is twice the diameter of circle B, then the radius of A is twice the radius of B.


Area is pi%2Ar%5E2, so square the factor. 2%5E2+=+4 The area of the larger circle is four times the area of the smaller circle.


Try it with a specific example. A: Diameter = 4, so radius = 2 B: Diameter = 2, so radius = 1.


Area A = pi%2A2%5E2+=+4pi


Area B = pi%2A1%5E2+=+pi


Area A is four times area B.