6.2 Students will use proportions to solve percentage problems.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

425

24 50

3 8

14

6.2 Students will use proportions to solve percentage problems.

Explain It!

Brand

ABrand

B

6.2 Students will use proportions to solve percentage problems.

General ObjectiveStudents will use proportions to solve

percentage problems.

6.2 Students will use proportions to solve percentage problems.

Where do we use percents?

6.2 Students will use proportions to solve percentage problems.

The Percent Proportion

=number

100 part Whole (of)

12 is what % of 40?

6.2 Students will use proportions to solve percentage problems.

What percent of 92 is 66?

Example 1: Finding the Percent One Number Is of Another

Think: What number is to 100 as 66 is to 92?

=number

100 partwhole

Set up a proportion.

Substitute. n

100 6692

=

n 92 = 100 66

92n = 6600

Find the cross products.

Method 1: Set up a proportion to find the percent.

Simplify.

6.2 Students will use proportions to solve percentage problems. Additional Example 1 Continued

n ≈ 72

Divide both sides by 92.

66 is approximately 72% of 92.

Simplify.

92n = 6600 92 92

6.2 Students will use proportions to solve percentage problems.

What percent of 140 is 21?

Think: What number is to 100 as 21 is to 140?

=number

100 partwhole Set up a proportion.

Let n represent the percent. n

100 21140

=

n 140 = 100 21

140n = 2100

Find the cross products.

Try It! Example 1

Method 1: Set up a proportion.

Simplify.

6.2 Students will use proportions to solve percentage problems.

n = 15

Divide both sides by 140.

21 is 15% of 140.

Try It! Example 1 Continued

Simplify.

140n = 2100 140 140

6.2 Students will use proportions to solve percentage problems.Practice: Green: 1, 3 Red: 2, 5 Blue: 3, 4

1. What percent of 80 is 20?

2. What percent of 48 is 16?

3. 300 out of 1000 is what percent?

4. 70 is what percent of 35?

5. A bin contains 120 ears of white and yellow corn. Of these, 78 ears are yellow. What percent of the ears of corn are yellow? What percent are white?

25%

33 1/3%

30%

200%

65%; 35%

6.2 Students will use proportions to solve percentage problems.

Lesson Quiz: Part

Find each percent.

1. What percent of 75 is 15? 20%

6.2 Students will use proportions to solve percentage problems.

1. What percent of 75 is 15?

A. 5

B. 10

C. 20

D. 50

Lesson Quiz for Student Response Systems

6.2 Students will use proportions to solve percentage problems.

3. 120 is what percent of 50?

A. 12

B. 50

C. 240

D. 600

Lesson Quiz for Student Response Systems