An angle is in standard position if its vertex is located at the origin and one ray is on the positive x-axis. The ray on the x-axis is called the initial side and the other ray is called the terminal side.[br][br]The angle is measured by the amount of rotation from the initial side to the terminal side. If measured in a counterclockwise direction the measurement is positive. If measured in a clockwise direction the measurement is negative. (A negative associated with an angle's measure refers to its "direction" of measurement, clockwise.)[br][br]If two angles in standard position have the same terminal side, they are called coterminal angles.[br][br]Click on Play in the lower left or move the slider left and right.

The quadrantal angles are at what positions?[br]Between what angles do each of the four quadrants lie?