Coterminal and Reference Angles

Front

What is a coterminal angle?

Back

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° (or 2π radians).

Front

How do you find a positive coterminal angle for -45°?

Back

To find a positive coterminal angle, add 360°: -45° + 360° = 315°.

Front

What is the reference angle for 150°?

Back

The reference angle is the acute angle formed by the terminal side of the angle and the x-axis. For 150°, the reference angle is 180° - 150° = 30°.

Front

What quadrant is 570° located in?

Back

570° is located in Quadrant 3.

Front

What is the standard position of an angle?

Back

An angle is in standard position when its initial side is on the positive x-axis.

Front

In which quadrant is -570°?

Back

-570° is located in Quadrant 2.

Front

What are the coterminal angles of -225°?

Back

The positive coterminal angle is 135° and the negative coterminal angle is -585°.

Front

How do you find a coterminal angle for an angle measured in radians?

Back

To find a coterminal angle in radians, add or subtract multiples of 2π. For example, for 11π/3, add 2π to find 17π/3.

Front

What is the reference angle for 210°?

Back

The reference angle for 210° is 210° - 180° = 30°.

Front

What is the relationship between coterminal angles and reference angles?

Back

Coterminal angles can have the same reference angle, but they differ by full rotations (360° or 2π radians).