Math Connects, Course 3 123

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In a percent proportion, of the numbers, called

the part, is being compared to the quantity,

also called the base. The other ratio is the percent, written

as a fraction, whose base is .

BUILD YOUR VOCABULARY (pages 116–117)

EXAMPLE Find the Percent

34 is what percent of 136?

Since 34 is being compared to 136, is part and is

the whole. You need to fi nd the percent. Let n represent the percent.

partwhole

34 _ 136

= n _ 100

Write the percent proportion.

· = · n Find the cross products.

= Multiply.

= Divide each side by .

= Simplify.

So, 34 is of 136.

Check Your Progress 63 is what percent of 210?

5–3 Algebra: The Percent Proportion

MAIN IDEA

• Solving problems using the percent proportion.

KEY CONCEPT

Percent Proportion

part _

whole =

percent __

100

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5–3

124 Math Connects, Course 3

Copyright ©

Glencoe/M

cGraw

-Hill, a division of T

he McG

raw-H

ill Com

panies, Inc.EXAMPLE Find the Part

What number is 70% of 600?

The percent is 70, and the whole is 600. You need to fi nd the part. Let n represent the part.

partwhole

n _ 600

= 70 _ 100

Write the percent proportion.

n · 100 = 600 · 70 Find the cross products.

100n = Multiply.

100n _ 100

= 42,000

__ 100

Divide each side by .

n = Simplify.

So, is 70% of 600.

Check Your Progress What number is 40% of 400?

EXAMPLE Find the Base

BASEBALL From 1999 to 2001, Derek Jeter had 11 hits with the bases loaded. This was about 30% of his at bats with the bases loaded. How many times was he at bat with the bases loaded?

The percent is 30, and the part is 11 hits. You need to fi nd the whole number of hits.

partwhole

11 _ n = 30 _ 100

percent Write the percent proportion.

11 · = n · Find the cross products.

= Multiply.

≈ n Divide each side by 30.

He had about at bats with the bases loaded.

Check Your Progress BASEBALL In 2005, Alex Rodriguez had 194 hits. This was about 32% of his at bats. How many times was he at bat?

ORGANIZE ITBe sure to explain how to fi nd the percent, the part, and the base of a percent proportion. You also may want to show the ideas in a chart like the Concept Summary in your text.

Lesson 5-3

®

HOMEWORKASSIGNMENTPage(s):

Exercises:

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