Download Reading 8.4

Name ________________________________________ Date __________________ Class__________________
LESSON
8-4
Reading Strategies
Compare and Contrast
The diagram below summarizes the similarities and differences between
angles of elevation and angles of depression.
Angle of Elevation
Angle of Depression
Contrast
Diagram
an angle formed by a
horizontal line and a line
of sight to a point above
the line
the angle of elevation
from your eye to the top
of a building
Definition
an angle formed by a
horizontal line and a line
of sight to a point below
the line
Example
the angle of depression
from the top of a tower
to the ground below
Compare
Both are angles formed by a horizontal line and a line of sight.
Both can be used to find distances.
1. An angle of ______________________ is formed by a horizontal line and a line
of sight to a point above the line.
2. A person is standing 30 meters from the base of a building.
The angle of elevation to the top of the building is 35°.
How tall is the building? Round to the nearest meter.
______________________
3. Leo is sitting in a seat on top of a 200-foot high Ferris wheel
looking down at his brother Jason. The angle of depression
to Jason is 80°. How far is Jason from the base of the Ferris
wheel? Round to the nearest foot.
______________________
Original content Copyright © by Holt McDougal. Additions and changes to the original content are the responsibility of the instructor.
8-34
Holt McDougal Geometry
Reading Strategies
Practice C
1. 82 ft 10 in.
2. 5 ft 10 in.
1. elevation
3. 128 ft 8 in.
3. 35 ft
4. Possible answer: m∠C = 38° and
m∠ADB = 52°. These angles are
complementary. So UABD ∼ UACB.
Lamar can use similarity ratios to find the
AC AB
AB 2
distance AC:
=
or AC =
.
AB AD
AD
Subtracting AD from AC leaves CD, the
width of the river.
5. 7.5 m
8-5 LAW OF SINES AND LAW OF
COSINES
Practice A
6. 95.2 m
7. 9° or N 81° E; 17.9 km/h
1. elevation
2. depression
depression
elevation
depression
11.5 m
18 ft
4.
6.
8.
10.
12.
2. −0.84
3. −3.27
4. 0.99
5. −0.07
6. −0.84
7. 0.86
8. −0.98
11. cos B; c
elevation
depression
elevation
23 ft
35 ft
10.
2
sin B
b
=
sin C
c
12. 15.5
13. 32°
14. 7.9 ft
15. 33°
16. 3.2 in.
17. 92.4°
Practice B
Challenge
1.
21.4
2. tan θ =
31.4
1. 0.21
9. −1.00
Reteach
3.
5.
7.
9.
11.
2. 21 m
3. 34.3°
1. 0.93
2. −0.87
3. −0.31
4. 1.00
5. −0.63
6. −6.31
7. 0.17
8. −0.10
9. −1.96
10. 17.0 m
11. 2.8 in.
12. 61.1 km
13. 55°
14. 85°
15. 18°
16. 6.0 ft
17. 3.7 cm
18. 10.0 mi
19. 144°
20. 47°
21. 40°
Practice C
4.
⎛5⎞
5. m∠K = tan ⎝ 7 ⎟⎠
−1 ⎜
1.
6. 35.5°
Problem Solving
1. 120 ft
2. 154 m
3. 57 ft
5. H
4. A
6. C
7. J
2.
3 1
; ; 3
2 2
3.
3
1
;− ;− 3
2
2
Original content Copyright © by Holt McDougal. Additions and changes to the original content are the responsibility of the instructor.
A15
Holt McDougal Geometry