Angle instandard position and reference angles: [br]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.[br]Angles in quadrant I are their own reference angles.[br]Now, move the slider and see the location of reference angle.

Vera Hu-Hyneman SCCC selden, NY