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smc

geometry senior

Problem

In the adjoining figure, circle has diameter ; circle is tangent to circle and to at the center of circle ; and circle tangent to circle , to circle and . The ratio of the area of circle to the area of circle is
problem
(A)
(B)
(C)
(D)
Solution
Let and be the radius of and the radius of respectively. It follows that the radius of is Suppose is the foot of the perpendicular from to We construct the auxiliary lines, as shown below: In right we have and By the Pythagorean Theorem, we get In right we have and By the Pythagorean Theorem, we get We equate the expressions for then simplify: Therefore, the ratio of the area of to the area of is
Final answer
C