7-4 Percents
Warm UpWarm Up
Lesson PresentationLesson Presentation
Problem of the DayProblem of the Day
Lesson QuizzesLesson Quizzes
7-4 Percents
Warm UpWrite each fraction as a decimal.
1. 2.
Write each decimal as a fraction.
3. 0.375 4. 0.05
0.75 0.934__ 9
10 __
38__ 1
20 __
7-4 Percents
Problem of the Day
Wally wanted to change the scale of a drawing from 1 in. = 2 ft to 1 in. = 10 ft. The scale height of a building in the first drawing is 25 in. How high is the building in the new drawing?5 in.
7-4 Percents
MA.6.A.5.1 Use equivalent forms of fractions, decimals, and percents to solve problems.
Sunshine State Standards
7-4 Percents
Most states charge sales tax on items you purchase. Sales tax is a percent of the item’s price. A percent is a ratio of a number to 100.
You can remember that percent means “per hundred.” For example, 8% means “8 per hundred,” or “8 out of 100.”
7-4 Percents
If a sales tax rate is 8%, the following statements are true:
• For every $1.00 you spend, you pay $0.08 in sales tax.
• For every $10.00 you spend, you pay $0.80 in sales tax.
• For every $100 you spend, you pay $8 in sales tax.
Because percent means “per hundred,” 100% means “100 out of 100.” This is why 100% is often used to mean “all” or “the whole thing.”
7-4 Percents
Additional Example 1: Modeling Percent
Use a 10-by-10-square grid to model 17%.
A 10-by-10 square grid has 100 squares.
17% means “17 out of 100”
or .
Shade 17 squares out of 100 squares.
17100
___
7-4 Percents
Additional Example 2: Writing Percents as Fractions
Write 35% as a fraction in simplest form.
Write the percent as a fraction with a denominator of 100.
Write the fraction in simplest form.
35% = 35100
___
35 ÷ 5100 ÷ 5
_______ = 720 __
Written as a fraction, 35% is . 720 __
7-4 Percents
Check It Out: Example 2A
Write each percent as a fraction in simplest form.
65%
65100 ___ = 13
20 __
7-4 Percents
Check It Out: Example 2B
Write each percent as a fraction in simplest form.
20%
20100 ___ = 1
5 __
7-4 Percents
Check It Out: Example 2C
Write each percent as a fraction in simplest form.
76%
76100 ___ = 19
25 __
7-4 Percents
Additional Example 3: Life Science Application
Janell has 20% body fat. Write 20% as a fraction in simplest form.
Write the percent as a fraction with a denominator of 100.
Write the fraction in simplest form.
20% = 20100
___
20 ÷ 20100 ÷ 20
_______ = 1 5 __
Written as a fraction, 20% is . 1 5 __
7-4 Percents
Check It Out: Example 3
Timmy is a football player with 10% body fat. Write 10% as a fraction in simplest form.
10100 ___ 1
10 __=
7-4 Percents
Additional Example 4: Writing Percents as Decimals
Write 56% as a decimal.
Write the percent as a fraction with a denominator of 100.
Write the fraction as a decimal.
56% = 56100
___
Written as a decimal, 56% is 0.56.
100 56.000.56
–500 600
–6000
To divide by 100, move the decimal point two places to the left. 56 ÷ 100 = 0.56
Remember!
7-4 Percents
Check It Out: Example 4C
Write each percent as a decimal.
80%
80100 ___ 0.8 = 8
10 ___ =
7-4 Percents
Additional Example 5: Application
Water made up 85% of the fluids that Kirk drank yesterday. Write 85% as a decimal.
Write the percent as a fraction with a denominator of 100.
Write the fraction as a decimal.
85% = 85100
___
85 ÷ 100 = 0.85
Written as a decimal, 85% is 0.85.
7-4 Percents
Check It Out: Example 5
Water made up 95% of the fluids that Lisa drank yesterday. Write 95% as a decimal.
= 95100 ___ 0.95
Percents Group ProblemsSolve the following problems and check your answers with
the fellow members of your group.
In a survey, 100 dog owners were asked where their dogs sleep. The results are shown as percents.
What percent of the people responded “Other”?42% + 30% + 18% = 90% 100% – 90% = 10%
What percent of the people did not respond “Dog Bed”?100% - 18% = 82%
Where dogs sleep Percent
Owner’s bed 42%
Doghouse 30%
Dog bed 18%
Other ?
7-4 Percents
Lesson Quiz
Write each percent as a fraction in simplest form.
1. 52% 2. 29%
Write each percent as a decimal.
3. 17% 4. 86%
5. A store clerk has an 8% sales increase. Write
the increase as a fraction in simplest form and as
a decimal.
, 0.08
1325 __ 29
100 ___
0.17 0.86
225 __
7-4 Percents
1. Which of the following represents 15% as a fraction in simplest form?
A. B.
C. D.
Lesson Quiz for Student Response Systems
7-4 Percents
2. Which of the following represents 79% as a fraction in simplest form?
A. B.
C. D.
Lesson Quiz for Student Response Systems
7-4 Percents
3. Which of the following represents 26% as a decimal?
A. 2.6 B. 0.026
C. 0.26 D. 0.0026
Lesson Quiz for Student Response Systems
7-4 Percents
4. Which of the following represents 71% as a decimal?
A. 71 B. 0.71
C. 7.1 D. 0.071
Lesson Quiz for Student Response Systems