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Question
A piece of wire 20 cm long is bent into the form of an arc of a circle subtending an angle of 60° at its centre. Find the radius of the circle.
Solution
Length of arc of circle = 20 cm
Here, central angle θ = 60°
∴ Length of arc = `θ/360^circ xx 2π"r"`
⇒ 20 = `60^circ/360^circ xx 2π"r"`
⇒ `(20 xx 6)/(2π)` = r
∴ r = `60/π "cm"`
Hence, the radius of circle is `60/π`cm.
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