2-5
Exercises
California
Standards Practice
5.0,
15.0, 25.1, 25.2
KEYWORD: MA8CA 2-5
KEYWORD: MA8CA Parent
GUIDED PRACTICE
Vocabulary Apply the vocabulary from this lesson to answer each question.
1. What does it mean when two ratios form a proportion?
2. In your own words, write a definition of percent.
SEE EXAMPLE
1
p. 102
3. The ratio of the sale price of a jacket to the original price is 3 : 4. The original price is
$64. What is the sale price?
4. Chemistry The ratio of hydrogen atoms to oxygen atoms in water is 2 : 1. If an
amount of water contains 341 trillion atoms of oxygen, how many hydrogen atoms
are there?
SEE EXAMPLE
2
p. 102
Find each unit rate.
5. A computer’s fan rotates 2000 times in 40 seconds.
6. Twelve cows produce 224,988 pounds of milk.
SEE EXAMPLE
3
p. 103
Solve each proportion. Check your answer.
3 =_
1
7. _
z
8
f+3 7
10. _ = _
12
2
SEE EXAMPLE 4
p. 103
SEE EXAMPLE
5
p. 104
x =_
1
8. _
3 5
b =_
3
9. _
4
2
3 =_
s-2
12. _
14
21
3
-1 = _
11. _
5
2d
13. Find 75% of 40.
14. Find 12__12 % of 168.
15. Find 115% of 57.
16. Find 70% of 8.
17. What percent of 40 is 25?
18. What percent of 225 is 180?
19. Archaeology Stonehenge II in Hunt, Texas, is a scale model of the ancient
construction in Wiltshire, England. The scale of the model to the original is 3 : 5.
The Altar Stone of the original construction is 4.9 meters tall. Write and solve a
proportion to find the height of the Texas model of the Altar Stone.
PRACTICE AND PROBLEM SOLVING
Independent Practice
For
See
Exercises Example
20–21
22–23
24–27
28–33
34
1
2
3
4
5
Extra Practice
Skills Practice p. EP5
Application Practice p. EP25
20. Gardening The ratio of the height of a bonsai ficus tree to the height of a
full-size ficus tree is 1 : 9. The bonsai ficus is 6 inches tall. What is the height of
a full-size ficus?
21. Manufacturing At one factory, the ratio of defective light bulbs produced to
total light bulbs produced is about 3 : 500. How many light bulbs are expected to
be defective when 12,000 are produced?
Find each unit rate.
22. Four gallons of gasoline weigh 25 pounds.
23. Fifteen ounces of gold cost $6,058.50.
Solve each proportion. Check your answer.
v =_
-5
1
2 =_
4
2 =_
24. _
25. _
26. _
y
5
6 2
6
h
b+7
3 =_
27. _
10
20
2- 5 Solving Proportions
105