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 [math] 180 degree - \theta[/math] Angle in quadrant III, reference angle is [math] \theta - 180 degree [/math] Angle in quadrant IV, reference angle is [math] 360 degree - \theta[/math] Vera Hu-Hyneman, SCCC selden, NY