EXERCISES
A Practice by Example
Example 1
(page 242)
For more practice, see Extra Practice.
Write a ratio for each situation in three ways.
1. About one in every four people swims at least six times each year.
2. About 24 out of 25 Californians live in a metropolitan area.
3. A week has five school days and two weekend days.
Example 2
(page 242)
Example 3
(page 243)
Example 4
(page 243)
Express each ratio as a decimal.
4. 7i8
5. 18 to 5
6. 83
7. 12i25
8. Nutrition The U.S. Department of Agriculture (USDA) recommends
that no more than 30% (0.30) of your Calories come from fat. In a bowl
of Tastycrunch cereal, 15 out of 120 Calories are from fat. Is this within
the USDA recommendation? Explain.
Find two ratios equal to each ratio.
9. 212
100
10. 36
18
11. 26
54
12. 360
180
15. 16
56
9
16. 72
Write each ratio in simplest form.
13. 44
12
14. 18
8
17. Cars A jack for a car requires a force of 120 lb to lift a 3,000-lb car. In
simplest form, what is the ratio of the car’s weight to the force required
to lift the car?
B
18. Cooking To make pancake batter, you need 2 cups of water for every
3 cups of flour. You plan to use 9 cups of flour. Write a ratio for the
number of cups of water to the number of cups of flour you will use.
19. Writing in Math Explain to a friend how to write a ratio in simplest
form. Give an example.
Compare the ratios below. Tell whether they are equal or not equal.
3
20. 18
24 , 4
23. 16i3, 27i5
Careers Atmospheric
scientists study the effects
of chemicals on our
environment.
50
21. 12
24 , 100
24. 2 to 3, 24 to 36
1
22. 22
1 , 22
25. 6i7, 30i35
26. Chemistry A chemical formula shows the ratio of atoms in a substance.
The formula for carbon dioxide is CO2. This means carbon dioxide has
1 atom of carbon (C) for every 2 atoms of oxygen (O). Write the ratio
of hydrogen (H) atoms to oxygen atoms in the substances in parts (a)
and (b) below.
a. water, H2O
b. disinfectant, H2O2
c. Reasoning Ammonia has a ratio of 1 molecule of nitrogen (N) to
3 molecules of hydrogen. What is its chemical formula?
5-1 Ratios
243-245
Use the table for Exercises 27 and 28.
27. Which two rooms have the
same ratio of girls to boys?
Room 101 Room 104 Room 107
Girls
12
9
Boys
16
20
28. The students in Room 101
and Room 104 have one class
together. Using simplest form,
write the ratio of girls to boys for the combined class.
9
12
2PHM5eSE_0501_ta02
29. Sports A softball diamond measures 65 ft by 65 ft. A baseball diamond
measures 90 ft by 90 ft. Write each ratio described in parts (a) and (b)
below in simplest form.
a. the length of a side of a softball diamond to the length of a side of a
baseball diamond
b. the area of a softball diamond to the area of a baseball diamond
c. Reasoning Explain why the ratio of the sides is not equal to the
ratio of the areas.
30. Error Analysis Your math class includes 15 girls and 10 boys. Two new
students, a girl and a boy, enroll in your class. Your friend says the ratio
is the same as before. Explain why your friend is not correct.
31. Cars Antifreeze protects a car’s radiator.
One brand recommends mixing at least
2 parts antifreeze with every 1 part
water for protection to -828F.
a. List all of the ratios in the table that
provide that protection.
b. Reasoning You want a car with a
15-qt radiator to be protected. You
want to use the least amount of
antifreeze. How much antifreeze and
how much water should you use?
C
Antifreeze (qt) Water (qt)
8
4
7.5
3
12
3.5
9
8
1
18
32. A bag contains red, blue, and yellow marbles. The ratio of red marbles
to blue marbles is 1i4. The ratio of blue marbles to yellow marbles is
2i5. What is the ratio of red marbles to yellow marbles?
33. Stretch Your Thinking The pattern at the right
uses nine toothpicks. How can you form five
triangles by moving only three toothpicks?
243-245
Mixing Antifreeze
Chapter 5 Ratios, Rates, and Proportions
Test Prep
Multiple Choice
34. Which ratio is equal to the ratio 50
12 ?
A. 6 to 25
B. 12
50
C. 25i6
6
D. 25
35. Which of the following ratios is written in simplest form?
Take It to the NET
Online lesson quiz at
www.PHSchool.com
Web Code: aba-0501
Extended Response
8
F. 52
G. 15
65
H. 27
81
9
I. 14
36. Which of the following ratios is NOT equal to the ratio 25 ?
6
A. 10
8
B. 20
C. 12
30
D. 14
35
37. A triangle has a base of 9 cm and a height of 16 cm. A similar
triangle’s base and height are 3 times larger. Using A = 12 bh, find the
area of each triangle. What is the ratio of the area of the second
triangle to the area of the first triangle?
Mixed Review
Lesson 2-4
Algebra
Solve each equation.
38. 72 = 8x
Lesson 1-1
q
39. 6 + y = 51
40. -5 = 7
42. 23.5 + 23.1
43. 28.7 4 5.4
Estimate.
41. 412 ? 83
5-1 Ratios
243-245