8 2 The Percent Equation

8.2 The Percent Equation

Solve problems by using the percent equation

Turn and Talk

• What have we been talking about for the past couple of weeks?

• Why do we need to know how to use percents?

• What are some examples of surveys that would use percents?

Pie Preferences

• Suppose 100 people were surveyed, how many preferred cherry pie?

Pie Preferences

• Suppose 120 people were surveyed, how many people preferred pumpkin pie?

T-table

• What does **is** mean?• What does **of** mean?

• PROPORTION• %/100=part/whole

• EQUATION:Part = Percent (whole)

Example 1

• What number is 12% of 350?

Example 2

• 21 is what percent of 40?

• On graph paper make a box with 40 squares inside.

• Shade in 21 boxes.

• About what percent is shaded?

• Find the exact answer.

I have a quiz with a score of 90. What are different ways you could

have received that score?

Example 3

• 13 is 26% of what number?

Example 4

• What number is 46% of 200?

Example 5

• 26 is what percent of 32?

Example 6

• 12 is 40% of what number?

• 2 group members choose a different rectangle to cut out on graph paper.

• 8 by 12

• 5 by 6

• The fold the rectangle into quarters and shade one of the quarters.

• How many squares are shaded?

• What is 25% of 96?

• What is 25% of 30?

Example 7

• What percent of 125 is 75?

Example 8

• 39 is 84% of what number?

Finland has the highest percent of people who have cell phones,

67.8%. If there are about 3,499,000 people with cell phones, what is the population of Finland?

In the year 2000, 102.2 million homes in the US had at least one

television. Of these, 86% also had VCRs. How many homes had

VCRs?

ESTIMATIONchoose the correct answer

• What percent of 56 is 14?

a. 2%

b. 72%

c. 25%

d. 50%

ESTIMATIONchoose the correct answer

• 36 is what percent of 40?

a. 90%

b. 48%

c. 25%

d. 73%

ESTIMATIONchoose the correct answer

• 80 is 40% of what number?

a. 80

b. 60

c. 200

d. 160

ESTIMATIONchoose the correct answer

• 65% of what number is 78?

a. 90

b. 42

c. 300

d. 120

Journal

• Explain how you knew the answer on the previous 4 estimation problems.

Workbook section 8-2

• 1st column

Homework

• p 342: 7, 8-22 even, 24, 27, 28