What are coterminal angles?
As discussed below.
Coterminal Angles are angles who share the same initial side and terminal sides. Finding coterminal angles is as simple as adding or subtracting 360° or 2π to each angle, depending on whether the given angle is in degrees or radians.
For example, the angles 30°, –330° and 390° are all coterminal.
What is the terminal side?
Standard Position of an Angle - Initial Side - Terminal Side. An angle is in standard position in the coordinate plane 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.