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Question
In the given figure, PSR, RTQ and PAQ are three semicircles of diameter 10 cm, 3 cm and 7 cm respectively. Find the perimeter of shaded region. [Use π= 3.14]
Solution
Perimeter of shaded region = Length of the arc PAQ + Length of the arc PSR + Length of the arc RTQ
`=1/2xx2pi"r"_1 + 1/2 xx 2pi"r"_2 + 1/2xx 2pi"r"_3`
`=1/2xx2pi(7/2)+1/2xx2pi(10/2)+1/2xx2pi(3/2)`
`=7/2pi + 5pi + 3/2pi`
`=7/2pi+3/2pi+5pi`
=5π + 5π
= 10π
= 31.4 cm
Hence, the perimeter of shaded region is 31.4 cm.
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