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Question
The radii of two circles are 25 cm and 18 cm. Find the radius of the circle which has a circumference equal to the sum of circumferences of these two circles.
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Solution
Circumference of the first circle
S1 = 2π x 25
= 50π cm
Circumference of the second circle
S2 = 2π x 18
= 36π cm
Let r be the radius of the resulting circle.
2πr = 50π + 36π
2πr = 86π
r = `(86π)/(2π)`
= 43 cm
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