College Trigonometry, 2011a

10.1 Angles and their Measure 715
27.
15π
is a Quadrant IV angle
4
coterminal with 7π 4 and −π 4
4
3
2
1
−4 −3 −2 −1
−1
1 2 3 4
−2
−3
−4
y
x
28. − 13π is a Quadrant IV angle
6
coterminal with 11π
6 and −π 6
4
3
2
1
−4 −3 −2 −1
−1
1 2 3 4
−2
−3
−4
y
x
29. 0 30.
33. − 7π 4
34.
4π
3
5π
6
31.
35.
3π
4
π
4
32. − 3π 2
36. − 5π 4
37. 180 ◦ 38. −120 ◦ 39. 210 ◦ 40. 330 ◦
41. 60 ◦ 42. 300 ◦ 43. −30 ◦ 44. 90 ◦
45. t = 5π 6
46. t = −π
y
y
1
1
1
x
1
x
47. t =6
y
48. t = −2
y
1
1
1
x
1
x