Examples - Reference Angle

In order to ensure that we understand this concept, let's look at some specific examples involving reference angles.

First, let theta=330 degrees. This angle lies in Quadrant IV and makes a 30° angle with the x-axis. Hence, the reference angle here is theta* = 30 degrees.

[reference angle diagram]

Next, let theta=-120 degrees. This angle lies in Quadrant III and makes a 60° angle with the x-axis. Hence, theta* = 60 degrees.

[reference angle diagram]


James A. Sellers