Coterminal Angles, Reference Angles, Degrees and Radians

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 reference angle for an angle in standard position?

Back

The reference angle is the acute angle formed by the terminal side of the given angle and the x-axis. It is always positive and can be found by taking the absolute value of the angle's measure and subtracting it from 180° or 360°, depending on the quadrant.

Front

What is the reference angle for an angle measuring 300°?

Back

The reference angle for 300° is 60°.

Front

What is the reference angle for an angle measuring -45°?

Back

The reference angle for -45° is 45°.

Front

How do you convert radians to degrees?

Back

To convert radians to degrees, multiply the radian measure by 180/π.

Front

Convert π/3 radians into degrees.

Back

π/3 radians is equal to 60°.

Front

What is the reference angle for 210°?

Back

The reference angle for 210° is 30°.

Front

What are the positive and negative coterminal angles of 150°?

Back

The positive coterminal angle is 510° and the negative coterminal angle is -210°.

Front

What is the reference angle for an angle measuring 400°?

Back

The reference angle for 400° is 40°.

Front

How do you find the coterminal angle of -720°?

Back

To find the coterminal angle, add 360° until the angle is positive. -720° + 720° = 0°, so the coterminal angle is 0°.