A pendulum swings through an angle of 30° and describes an arc 8.8 cm in length. Find the length of the pendulum.

Given:

Angle made by the pendulum = 30°


Length of the arc made by the pendulum = 8.8 cm


Then the length of the pendulum is equal to the radius of the sector made by the pendulum.


Let the length of the pendulum be ‘r’.


Length of arc = × 2πr


We have,


× 2πr = 8.8


× 2 × 3.14 × r = 8.8


r = 8.8 ×


r = 16.8 cm


Hence, the length of the pendulum is 16.8 cm.


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