Geometry Trigonometry & Applications 4

Question 1

Convert 180° to radians.

Accepted Answer

π

Answer

180° equals π radians by definition.

Question 2

What is the reference angle for 210°?

Accepted Answer

30°

Answer

210° is in the third quadrant; its reference angle is 210° − 180° = 30°.

Question 3

In which quadrant is sine positive but cosine negative?

Accepted Answer

Second

Answer

In quadrant II, sine is positive and cosine is negative.

Question 4

What is cos 120°?

Accepted Answer

−1/2

Answer

120° has reference angle 60° in quadrant II, so cos 120° = −cos 60° = −1/2.

Question 5

Convert π/3 radians to degrees.

Accepted Answer

60°

Answer

π/3 × 180°/π = 60°.

Geometry Practice Test