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Question
The sum of the radii of two circles is 10.5 cm and the difference of their circumferences is 13. 2 cm. Find the radii of the two circles.
Solution
The sum of the radii = 10.5 cm
r1 + r2 = 10.5 cm .............. (i)
The difference of circumferences= 13.2 cm
2 π (r1 - r1) = 13.2
(r1 - r1) = `13.2/(2 pi)`
(r1 - r1) = `(13.2 xx 7)/(2 xx 22)`
r1 - r1 = 2.1 ........(ii)
Adding (i) and (ii)
2r1 = 12.6
r1= 6.3 cm
Therefore, r2 = (10.5 - 6.3) cm= 4.2 cm
Hence, the two radii are 6.3 cm and 4.2 cm
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