A pendulum in a grandfather clock is 7 feet long and swings

A pendulum in a grandfather clock is 7 feet long and swings back and forth along a 9 inch arc. Approximate the angle (in degrees) the pendulum passes on 1 swing

Solution

length of pendulum = 7 feet = 84 inches

angle = arc length / radius

angle = 9 / 84 = .107142 radians

converting radians to degrees

angle = 6.14 degrees