A pendulum swings through an angle of 30∘ and describes an arc 8.8 cm in length. Find the length of pendulum in cm.
16.8
Let r be the length of the pendulum
Length of arc = 8.8 cm
∠AOB = 30 ∘
Length of an arc of a sector of an angle θ
=θ360×2πr
Length of arc
=θ360×2πr
8.8=30360×2×227×r
r=8.8×2111=16.8 cm