Reference angle

Hi, I need to.........

find the reference angle for an angle of 220 degrees.
--and-
Fine the reference angle for an angle of 5pi / 3


THANK YOU!

If you imagine the unit circle a reference angle is the smallest angle difference between the given angle and the x-axis (which is at 0 or 180 degrees).

In the case of 220 it is closest to 180 so the reference angle is 40 degrees