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Question
Calculate the length of the arc of a circle of radius 31.0 cm which subtends an angle of `pi/6` at the centre.
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Solution
Plane Angle α = `"Arc length"/"Radius" = s/r`
According to the problem, θ = `pi/6 = s/31` cm
Hence, length of arc = s = `31 xx pi/6` cm`
= `(31 xx 3.14)/6` cm
= 16.22 cm
Rounding off to three significant figures it would be 16.2 cm.
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