High School Math : Understanding Angles in the Unit Circle

Example Questions

Example Question #52 : The Unit Circle And Radians

In the unit circle, what is the angle in radians that corresponds to the point (0, -1)?

Explanation:

On the unit circle, (0,-1) is the point that falls between the third and fourth quadrant.  This corresponds to .

Example Question #51 : The Unit Circle And Radians

What is the reference angle for ?