Unit Circle 5: 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°.

Front

How do you find a reference angle for an angle in standard position?

Back

To find the reference angle, subtract the angle from 360° if it's in the fourth quadrant, subtract 180° if it's in the second quadrant, or subtract the angle from 180° if it's in the third quadrant.

Front

Which trigonometric functions are positive in Quadrant I?

Back

In Quadrant I, all trigonometric functions (sine, cosine, tangent, secant, cosecant, and cotangent) are positive.

Front

Which trigonometric functions are positive in Quadrant II?

Back

In Quadrant II, sine and cosecant are positive, while cosine, tangent, secant, and cotangent are negative.

Front

Which trigonometric functions are positive in Quadrant III?

Back

In Quadrant III, tangent and cotangent are positive, while sine, cosine, secant, and cosecant are negative.

Front

Which trigonometric functions are positive in Quadrant IV?

Back

In Quadrant IV, cosine and secant are positive, while sine, tangent, cosecant, and cotangent are negative.

Front

What is the reference angle for 250°?

Back

The reference angle for 250° is 70°.

Front

What is the reference angle for -150°?

Back

The reference angle for -150° is 30°.

Front

How do you calculate a positive coterminal angle?

Back

To find a positive coterminal angle, add 360° to the given angle.

Front

How do you calculate a negative coterminal angle?

Back

To find a negative coterminal angle, subtract 360° from the given angle.