7th Grade Math

Find the Percent

What percent of $15 is $9?

Words

Variable

Proportion

What percent of $15 is $9?

Let n% represent the percent.

part

_whole _ 159 = _ 100 n percent

_^9

15

= _n

100

Write the proportion.

9 · 100 = 15 · n Find the cross products.

900 = 15 n Simplify.

_^900

15

= _^15 n

15

Divide each side by 15.

60 = n

So, $9 is 60% of 15.

a. What percent of 25 is 20? b. $12.75 is what percent of $50?

Find the Part

What number is 40% of 120?

Words

Variable

Proportion

What number is 40% of 120?

Let p represent the part.

part

_whole

p

_ 120 = _ 10040 percent

p

_

120

= _^40

100

Write the proportion.

p · 100 = 120 · 40 Find the cross products.

100 p = 4,800 Simplify.

100 p

_

100

=

4,800

_

100

Divide each side by 100.

p = 48

So, 48 is 40% of 120.

c. What number is 5% of 60? d. 12% of 85 is what number?

The Percent Proportion The Percent Proportion

The whole usually comes

after the word of.

Lesson 2B Proportions and Equations 333

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