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.
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.)
If two angles in standard position have the same terminal side, they are called coterminal angles.
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The quadrantal angles are at what positions?
Between what angles do each of the four quadrants lie?