# Coterminal Angles

Coterminal angles are angles in standard position (angles with the initial side on the positive $x$ -axis) that have a common terminal side. For example, −330°and 390°are all coterminal.

To find a positive and a negative angle coterminal with a given angle, you can add and subtract 360°if the angle is measured in degrees or 2π if the angle is measured in radians.

Example 1:

Find a positive and a negative angle coterminal with a 55°angle.

55°−360°=−305°55°+360°=415°

A −305°angle and a 415°angle are coterminal with a 55°angle.* *

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Example 2:

Find a positive and a negative angle coterminal with a π3 angle.

π3+2π=7π3π3−2π=−5π3

A 7π3 angle and a −5π3 angle are coterminal with a π3 angle.

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Reference - https://www.varsitytutors.com/hotmath/hotmath_help/topics/coterminal-angles

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