Coterminal and Reference Angles

Front

What is a reference angle?

Back

The reference angle is the acute angle formed by the terminal side of an angle in standard position and the x-axis.

Front

How do you find the reference angle for an angle in the first quadrant?

Back

The reference angle is the angle itself.

Front

How do you find the reference angle for an angle in the second quadrant?

Back

Subtract the angle from 180°.

Front

How do you find the reference angle for an angle in the third quadrant?

Back

Subtract 180° from the angle.

Front

How do you find the reference angle for an angle in the fourth quadrant?

Back

Subtract the angle from 360°.

Front

What is a coterminal angle?

Back

Coterminal angles are angles that share the same terminal side when drawn in standard position, differing by full rotations of 360°.

Front

How do you find a coterminal angle for a given angle?

Back

Add or subtract multiples of 360° to the given angle.

Front

What is the coterminal angle of -90°?

Back

-90° + 360° = 270°.

Front

What is the direction of positive angle measurement from standard position?

Back

Counterclockwise.

Front

What is the direction of negative angle measurement from standard position?

Back

Clockwise.