Angle instandard position and reference angles

Topic:
Angles
Angle instandard position and reference angles: The reference angle is the acute angle formed by the terminal side of the given angle and the x-axis. Reference angles may appear in all four quadrants. The refernce angle is measured from the terminal side of original angle TO the x-axis, not the y-axis. Angles in quadrant I are their own reference angles. Now, move the slider and see the location of reference angle.
Now, Answer the following questions: How do you calculate reference angle algebraically? Answer: Angle in quadrant I, reference angle is angle itself. Angle in quadrant II, reference angle is Angle in quadrant III, reference angle is Angle in quadrant IV, reference angle is Vera Hu-Hyneman, SCCC selden, NY