Question

A piece of wire 22 cm long is bent into the form an arc of a circle subtending an angle of 60° at its centre. Find the radius of the circle. `["Use"  π = 22/7]`

Answer 1

AB is an arc of a circle.

i.e., AB = 22 cm

And θ = 60°

∴ Length of an arc = `(2πrθ)/360^circ`

⇒ `22 = (2 xx 22 xx r xx 60^circ)/(7 xx 360^circ)`

⇒ `22 = (2 xx r)/21`

⇒ 22 × r = 22 × 21

⇒ r = 21

Hence, the radius of the circle (r) is 21 cm.