Question

A ball is attached to the moving end of the 5-meter arm of a pendulum. The pendulum swings through a 90 degree arc once. How far in meters, does the ball travel?

Answer 1

(pi/2) * R, where R = 5 meters

That is 1/4 of the circumference of a circle with radius R

Answer 2

1/4 divided by 3.14 x 10 is 7.9 meters