Reference Angles

Front

What is a reference angle?

Back

A 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 a negative angle?

Back

To find the reference angle for a negative angle, add 360° to the angle until it is positive, then find the reference angle as you would for a positive angle.

Front

What is the reference angle for -30°?

Back

30°

Front

In which quadrants are sine, cosine, and tangent positive?

Back

In Quadrant I, all trigonometric ratios (sin, cos, tan) are positive.

Front

What is the reference angle for 120°?

Back

The reference angle for 120° is 180° - 120° = 60°.

Front

How do you find the cotangent of an angle using its reference angle?

Back

To find the cotangent of an angle, use the cotangent of its reference angle and consider the sign based on the quadrant.

Front

What is the cotangent of 120°?

Back

The cotangent of 120° is -√3/3.

Front

What is the reference angle for 330°?

Back

The reference angle for 330° is 360° - 330° = 30°.

Front

How do you find the cosecant of an angle using its reference angle?

Back

To find the cosecant of an angle, use the cosecant of its reference angle and consider the sign based on the quadrant.

Front

What is the cosecant of 330°?

Back

The cosecant of 330° is -2.