1/6 - Tuesday - Coterminal and Reference Angles (Degrees)

The reference angle is the acute angle formed by the terminal side of an angle and the x-axis. It is always between 0° and 90°.

Subtract the angle from 180°. For example, for 112°, the reference angle is 180° - 112° = 68°.

Subtract 180° from the angle. For example, for 248°, the reference angle is 248° - 180° = 68°.

Subtract the angle from 360°. For example, for 300°, the reference angle is 360° - 300° = 60°.

Coterminal angles are angles that share the same terminal side when drawn in standard position. They can be found by adding or subtracting multiples of 360°.

Add 360°: 73° + 360° = 433°.

Add 360°: -117° + 360° = 243°.

Coterminal angles can be found using the formula: angle ± 360°n, where n is any integer.

Subtract 360°: 492° - 360° = 132°.

The reference angle is 180° - 163° = 17°.