Pre-Algebra Chapter 9

18. RIDES Suppose a roller coaster casts a shadow of 31.5 feet. At the same
time, a nearby Ferris wheel casts a 19-foot shadow. If the roller coaster is
126 feet tall, how tall is the Ferris wheel?
19. CRITICAL THINKING Michael is using three similar triangles to build
a kite. One of the triangles measures 2 units by 3 units by 4 units. How
large can the other two triangles be?
Standardized
Test Practice
20. WRITING IN MATH Answer the question that was posed at the beginning
of the lesson.
How can similar triangles be used to create patterns?
Include the following in your answer:
• an explanation telling how Sierpinski’s triangle relates to similarity, and
• an example of the pattern formed when Steps 1–4 are performed on an
acute scalene triangle.
21. The triangles shown are similar.
Find the length of JM to the
nearest tenth.
A 3.7 B 3.9
C 4.1 D 8.3
R
5.5 ft
J
x ft
22. On the coordinate system, MNP
and two coordinates for RST are
shown. Which coordinate for point
T will make MNP and RST
similar triangles?
A T(3, 1) B T(1, 1)
C
T(1, 2) D T(1, 1)
S 3 ft T K 2 ft M
y
M N
O
x
P R S
Maintain Your Skills
Mixed Review
Find the distance between each pair of points. Round to the nearest tenth,
if necessary. (Lesson 9-6)
23. S(2, 3), T(0, 6) 24. E(1, 1), F(3, 2) 25. W(4, 6), V(3, 5)
If c is the measure of the hypotenuse, find each missing measure. Round to
the nearest tenth, if necessary. (Lesson 9-5)
26. a 8, b ?, c 34 27. a ?, b 27, c 82
28. ALGEBRA Write an equation for the line that passes through points at
(1, 1) and (2, 11). (Lesson 8-7)
Getting Ready for
the Next Lesson
www.pre-alg.com/self_check_quiz
Write each percent as a fraction in simplest form. (Lesson 6-4)
29. 25% 30. 87 1 % 31. 150%
2
PREREQUISITE SKILL Express each fraction as a decimal. Round to four
decimal places, if necessary. (To review writing fractions as decimals, see Lesson 5-1.)
32. 1 2
33. 1 0
34. 2 0
9
35.
16
14
25
4 0
Lesson 9-7 Similar Triangles and Indirect Measurement 475