Question

A pendulum swings through an angle of 20 degrees each second. If the pendulum is 40 inches long, how far does its tip move each second?
noel
to answer this question you need to know the formula for the circumference of a circle is: circumference = pi * 2r and a circle is 360 degrees.

so the length of the arc is what fraction of the whole circle?

and that fraction times the above circumference formula is your answer