Angles of Elevation and Depression GEOMETRY LESSON 9-3 Pages 484-488 Exercises 1. of elevation from sub to boat 2. of depression from boat to sub 3.  of elevation from boat to lighthouse 4. of depression from lighthouse to boat 5. of elevation from Jim to waterfall 6. of elevation from Kelley to waterfall 7. of depression from waterfall to Jim 8. of depression from waterfall to Kelley 9. 34.2 ft 10. 502.4 m 11. 32.2 m 12. 86.6 ft 13. about 986 m 14. 51.3 ft 15. 777.9 m 16. 263.3 yd 17. 0.6 km 18. 769 ft 19. 64° 20. 4.8° 9-3

Angles of Elevation and Depression GEOMETRY LESSON 9-3 21. about 194 m 22. a-b Check students’ work. 23. 3300 m 24. 72, 72 25. 46, 46 26. 27, 27 27. 20, 20 28. a. 560 ft 28. (continued) b. about 15.9° 29. a. Length of any guy wire = dist. on the ground from tower to the guy wire div. by the cosine of the formed by the guy wire and the ground. 29. (continued) b. Height of attachment = dist. on the ground from tower to the guy wire times the tangent of the formed by the guy wire and the ground. 30. 5 31. about 2.8 32. 0.5; about 84.9 9-3

Angles of Elevation and Depression GEOMETRY LESSON 9-3 33. 370 m 34. about 28 ft 35. Measure the length of the stick and the shortest shadow. The tangent of the angle of elevation is the ratio of the length of the stick to the length of the shadow. Then use inverse tangent. 36. Check students’ work. 37. C 38. F 39. B 40. A 41. C 42. A 43. C 44. [2] a. b. Let h represent the height of the tree. h ≈ 6 + 12 tan 83º h ≈ 6 + 12(8.14) ≈ 6 + 98 = 104 The tree is about 104 ft tall. 9-3

Angles of Elevation and Depression GEOMETRY LESSON 9-3 44. [1] correct drawing OR correct solution without work shown 45. 85.2 m 46. 38.2 ft 47. 45 48. 70 49. 110 50. 60 51. 130 52. 240 53. 230 54. x = 9; 60, 30, 40, 30 55. y = 3, x = 2; 16, 10, 10, 16 9-3