Reference Angle

The reference angle is the positive acute angle that can represent an angle of any measure. Basically, any angle on the x-y plane has a reference angle, which is always between 0 and 90 degrees. The reference angle is always the smallest angle that you can make from the terminal side of an angle (ie where the angle ends) with the x-axis. A refrerence angle always uses the x-axis as its frame of rerence.