Coterminal Angles and Reference Angles (degrees only)

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 degrees.

Front

How do you find a coterminal angle?

Back

To find a coterminal angle, add or subtract 360 degrees from the given angle until you reach the desired range (0 to 360 degrees).

Front

What is a reference angle?

Back

A 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 degrees.

Front

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

Back

For an angle in the second quadrant, subtract the angle from 180 degrees to find the reference angle.

Front

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

Back

For an angle in the third quadrant, subtract 180 degrees from the angle to find the reference angle.

Front

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

Back

For an angle in the fourth quadrant, subtract the angle from 360 degrees to find the reference angle.

Front

What is the reference angle for 115 degrees?

Back

The reference angle for 115 degrees is 180 - 115 = 65 degrees.

Front

What is the reference angle for 398 degrees?

Back

First, find the coterminal angle: 398 - 360 = 38 degrees. The reference angle is 38 degrees.

Front

What is the coterminal angle of 25 degrees?

Back

Coterminal angles can be found by adding or subtracting 360 degrees. For example, 25 + 360 = 385 degrees.

Front

What is the coterminal angle of -205 degrees?

Back

To find a positive coterminal angle, add 360 degrees: -205 + 360 = 155 degrees.