Warm Up

1

• Warm Up
• Rewrite each value as indicated.
• 1. as a percent
• 2. 25 as a fraction
• 3. as a decimal
• 4. 0.16 as a fraction

48
0.375
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Additional Example 1 Finding the Percent One
Number Is of Another
What percent of 92 is 66?
Method 1 Set up a proportion to find the percent.
Think What number is to 100 as 66 is to 92?
Set up a proportion.
Substitute.
n ? 92 100 ? 66
Find the cross products.
92n 6600
Simplify.
3
Additional Example 1 Continued
Divide both sides by 92.
Simplify.
n 72
66 is approximately 72 of 92.
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Additional Example 1 Continued
What percent of 92 is 66?
Method 2 Set up an equation.
percent ? whole part Set up an equation.
p ? 92 66 Let p represent the percent.
Divide both sides by 92.
p ? 0.72 Simplify.
66 is about 72 of 92.
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Additional Example 1 Continued
Check
66.24 ? 66 72 of 92 is approximately 66.
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Check It Out! Example 1
What percent of 140 is 21?
Method 1 Set up a proportion.
Think What number is to 100 as 21 is to 140?
Set up a proportion.
Let n represent the percent.
n ? 140 100 ? 21
Find the cross products.
140n 2100
Simplify.
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Check It Out! Example 1 Continued
Divide both sides by 140.
n 15
Simplify.
21 is 15 of 140.
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Check It Out! Example 1 Continued
What percent of 140 is 21?
Method 2 Set up an equation.
percent ? whole part Set up an equation.
p ? 140 21 Let p represent the percent.
Divide both sides by 140.
p 0.15 Simplify.
21 is 15 of 140.
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Check It Out! Example 1 Continued
Check
21 21 15 of 140 is approximately 21.
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Additional Example 2A Recreation Application
Four friends volunteered to cut the grass around
their neighbors house. Jay cut 23 of the
grass, Aimee cut of the grass, Ken cut 0.31
of the grass, and Bryn cut the rest. What percent
of the grass did Bryn cut?
1 5
First, find what percent of the grass Aimee and
Ken cut.
Next, subtract the percents you know from 100 to
find the remaining percent.
100 23 20 31 26.
Bryn cut 26 of the grass.
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Additional Example 2B Recreation Application
Jeremy organizes his movie collection by
genre.
of his collection are dramas, 0.325 are
action films, 3 are documentaries, 19.5 are
comedies, and the rest of his movies are
independent films. What percent of his movie
collection are independent films?
2 5
First, find what percent of his films are dramas
and action.
Next, subtract the percents you know from 100 to
find the remaining percent.
100 40 32.5 3 19.5 5.
5 of Jeremys movie collection are independent
films.
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Check It Out! Example 2A
Four store employees stock the shelves at the
Electronics Store. Francisco stocked 14 of the
shelves, Lauren stocked of the shelves, Ling
stocked 0.19 of the shelves, and Mark stocked the
rest. What percent of the shelves did Mark stock?
3 5
First, find what percent of the shelves Lauren
and Ling stocked.
Next, subtract the percents you know from 100 to
find the remaining percent.
100 14 60 19 7.
Mark stocked 7 of the shelves.
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Check It Out! Example 2B
Joe organizes his CD collection by genre.
of his collection is rock, 0.125 is
pop, 6 is classical, 9.5 is country, and the
rest of his CDs are jazz. What percent of his CD
collection is jazz?
1 2
First, find what percent of his CDs are rock and
pop.
Next, subtract the percents you know from 100 to
find the remaining percent.
100 50 12.5 6 9.5 22.
22 of Joes CD collection is jazz.
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Additional Example 3A Finding the Percent of a
Number
The city of Dallas, Texas has a population of
approximately 1,189,000 people. The population of
the city of Austin, Texas is 55 of the
population of Dallas. To the nearest thousand,
what is the population of Austin?
Choose a method Set up a proportion.
Think 55 is to 100 as what population is to
1,189,000?
Set up a proportion.
55 ? 1,189,000 100 ? p Find the cross
products.
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Additional Example 3A Continued
65,395,000 100p
Simplify.
Divide both sides by 100.
653,950 p
Simplify.
654,000 p
Round to the nearest whole number.
Austin has a population of approximately 654,000
people.
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Additional Example 3B Finding the Percent of a
Number
After a drought, a reservoir had only 66
of the average amount of water. If the average
amount of water is 57,000,000 gallons, how much
water was in the reservoir after the drought?
Choose a method Set up an equation.
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Additional Example 3B Continued
w 38,000,000
Simplify.
The reservoir contained 38,000,000 gallons of
water after the drought.
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Check It Out! Example 3A
After a drought, a river had only 50 of
the average amount of water flow. If the average
amount of water flow is 60,000,000 gallons per
day, how much water was flowing in the river
after the drought?
Choose a method Set up an equation.
w ? 30,400,000
Simplify.
The water flow in the river was about 30,400,000
gallons per day after the drought.
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Check It Out! Example 3B
Ms. Marvin has a savings account with
approximately 214,000 in it. Mr. Parson has 35
of the amount of Ms. Marvins savings account. To
the nearest thousand, what is the amount of Mr.
Parsons savings account?
Choose a method Set up a proportion.
Think 35 is to 100 as what amount is to 214,000.
Set up a proportion.
35 ? 214,000 100 ? s Find the cross
products.
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Check It Out! Example 3B Continued
7,490,000 100s
Simplify.
Divide both sides by 100.
74,900 s
Simplify.
75,000 s
Round to the nearest thousand.
Mr. Parson has approximately 75,000 in his
savings account.
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Lesson Review Part I
Find each percent. 1. What percent of 33 is 22?
2. Of Earths 197 million mi2 of surface area,
about 139 million mi2 is water. Find the percent
of Earths surface that is covered by water. 3.
The Ramirez family bought a large bag of oranges
during their trip to Florida. Jorge ate of the
oranges, Ann ate 0.18 of the oranges, Mrs.
Ramirez ate 22 of the oranges, and Mr. Ramirez
ate the rest. What percent of the oranges did Mr.
Ramirez eat?
70.6
25
20
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Lesson Review Part II
4. Rada is 170 as tall as her brother Raj. Raj
is 0.82 m tall. To the nearest tenth of a meter,
how tall is Rada? 5. The volume of Lake
Superior is 2900 mi3 and the volume of Lake Erie
is 116 mi3. What percent of the volume of Lake
Superior is the volume of Lake Erie?
1.4 m
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