Today’s Plan:-Warm Up-Percent -Assignment & Flashcard race

LT: I will use a proportion to solve percent problems.

Entry Task

04/12/10 Percent Calculations #28

Find the percent of each number.

1. 25% of 8

2. 40% of 110

3. 150% of 96

4. 0.3% of 120

44

2

144

0.36

Course 2

6-4 Solving Equations Containing Percents

Sloths may seem lazy, but their extremely slow movement helps to make them almost invisible to predators. Sloths sleep an average of 16.5 hours a day. To find out what percent of a 24-hour day 16.5 hours is, you can use a proportion or an equation.

Course 2

6-4 Solving Equations Containing Percents

Percent is

of

Sloths spend 68.75% of the day sleeping!

16.5 is what percent of 24 hours?

%100

= isof

x

100

16.5

24=

Course 2

6-4 Solving Equations Containing Percents

white boards…

%100

= isof

Course 2

6-4 Solving Equations Containing Percents

A. 25 is what percent of 40?

100=

62.5%

25 is 62.5% of 40.

%100

= isof

x 2540

Course 2

6-4 Solving Equations Containing Percents

B. 15 is 25% of what number?

x = 60

15 is 25% of 60.

Write a proportion.

%100

= isof

100=25 15

x

Solve.

Try This: Example 1A

Course 2

6-4 Solving Equations Containing Percents

A. 10 is what percent of 50?n

100= 10

50

n = 20

10 is 20% of 50.

Write a proportion.

Solve.

Try This: Example 1B

Course 2

6-4 Solving Equations Containing Percents

B. 8 is 40% of what number?

40100

= 8n

n = 20

8 is 40% of 20.

Write a proportion.

Today’s Plan:-Warm Up-Percent -Assignment & Flashcard race

LT: I will use a proportion to solve percent problems.

AssignmentPg 318 #1-21 and 23

For each problem show the proportion and your answer.

04/12/10 Percent Calculations #28

%100

= isof

Course 2

6-4 Solving Equations Containing Percents

Proportion Method Equation Method

n100

= 16.524

PartWhole

PartWhole

What percent of 24 is 16.5?

n · 24 = 100 · 16.5

24n = 1,650

n = 68.75 68.75%

n · 24 = 16.5

n = 0.6875

n = 68.75%

Solve.

Additional Example 2A: Using Equations to Solve Problems with Percents

Course 2

6-4 Solving Equations Containing Percents

A. 35 is 28% of what number?

35 = 28% · n

35 = 0.28 · n

350.28

= 0.28 · n0.28

125 = n

35 is 28% of 125.

Write an equation.

Write 28% as a decimal.

Divide each side by 0.28 to isolate the variable.

Solve.

Additional Example 2B: Using Equations to Solve Problems with Percents

Course 2

6-4 Solving Equations Containing Percents

B. 18 is what percent of 9?

18 = n · 9

189

= n · 99

2 = n

200% = n

18 is 200% of 9.

Write an equation.Divide each side by 9 to isolate the variable.Write the decimal as a percent.

Solve.

Try This: Example 2A

Course 2

6-4 Solving Equations Containing Percents

A. 36 is 24% of what number?

36 = 24% · n

36 = 0.24 · n

150 = n

36 is 24% of 150.

Write an equation.

Write 24% as a decimal.

Divide each side by 0.24 to isolate the variable.

360.24

= 0.24 · n0.24

Solve.

Try This: Example 2B

Course 2

6-4 Solving Equations Containing Percents

B. 36 is what percent of 6?

36 = n · 6

366

= n · 66

6 = n

600% = n

36 is 600% of 6.

Write an equation.Divide each side by 6 to isolate the variable.Write the decimal as a percent.

Workers in Canada earn 10 vacation days, and workers in Finland earn 30 vacation days. What percent of the vacation days that workers in Canada earn do workers in Finland earn?

Additional Example 3: Social Studies Application

Course 2

6-4 Solving Equations Containing Percents

n · 10 = 30

n · 1010

= 3010

n = 3.0

Workers in Finland earn 300% of the number of vacation days that workers in Canada earn.

Write an equation.

Divide each side by 10 to isolate the variable.

Write the decimal as a percent.

Restate the question: What percent of 10 is 30?

n = 300

Workers in Canada earn 10 vacation days, and workers in Britain earn 20 vacation days. What percent of the vacation days that workers in Canada earn do workers in Britain earn?

Try This: Example 3

Course 2

6-4 Solving Equations Containing Percents

n · 10 = 20

n · 1010

= 2010

n = 2.0

Workers in Britain earn 200% of the number of vacation days that workers in Canada earn.

Write an equation.

Divide each side by 10 to isolate the variable.

Write the decimal as a percent.

Restate the question: What percent of 10 is 20?

n = 200

Lesson Quiz

1. 21 is 42% of what number?

2. 73 is what percent of 292?

3. 112% of what number is 84?

4. 13.4 is what percent of 1340?

5. An ad shows a DVD player on sale for 75% of its original price. If its original price was $242, what is the sale price?

25%

50

Insert Lesson Title Here

75

1%

Course 2

6-4 Solving Equations Containing Percents

$181.50