Pre-Algebra Chapter 9

Practice and Apply
Homework Help
For
Exercises
See
Examples
13–20 1
21–26 2
27–32 3
33–36 4
Extra Practice
See page 747.
Find each sine, cosine, or tangent.
Round to four decimal places,
if necessary.
13. sin N 14. sin K
15. cos C 16. cos A
17. tan N 18. tan C
19. Triangle RST is shown. 20. For XYZ, what is the value
Find sin R, cos R, and tan R. of sin X, cos X, and tan X?
B
20
A
21
29
C
M
5
N
12
13
K
R
4
T
80
8
S
Y
X
74
5
7 Z
Use a calculator to find each value to the nearest ten thousandth.
21. sin 6° 22. sin 51° 23. cos 31°
24. cos 87° 25. tan 12° 26. tan 66°
For each triangle, find each missing measure to the nearest tenth.
27. 28. 29.
x
22
25˚
18˚
8
x
33
30. 31. 32.
x
73˚
16
x
47˚
91
41˚
x
13
62˚
x
Civil Engineer
Civil engineers usually
design and supervise the
construction of roads,
buildings, bridges, airports,
dams, and water supply
and sewage systems.
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For information
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civil engineer, visit:
www.pre-alg.com/
careers
33. SHADOWS An angle of elevation is formed by
a horizontal line and a line of sight above it. A
flagpole casts a shadow 25 meters long when
the angle of elevation of the Sun is 40°. How
tall is the flagpole?
34. SAFETY The angle that a wheelchair ramp forms with the ground
should not exceed 6°. What is the height of the ramp if it is 20 feet long?
Round to the nearest tenth.
35. BUILDINGS Refer to the diagram shown.
What is the height of the building?
40˚
25 m
x m
1.6 m
26.5˚
85 m
480 Chapter 9 Real Numbers and Right Triangles
36. CIVIL ENGINEERING An exit ramp makes a 17° angle with the highway.
Suppose the length of the ramp is 210 yards. What is the length of the
base of the ramp? Round to the nearest tenth.