Percents3.23.2

1. Write a percent as a fraction or decimal number.2. Write a fraction or decimal number as a percent.3. Translate and solve percent sentences.4. Solve problems involving percents.

ReviewReview

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ba

Ratio: A comparison of two quantities using a quotient (fraction).

Proportion: Two ratios set equal.

Cross Products:

Cross products are equal.

Percent:

20% = 20 out of 100

0

20

10

1 or 0.2

5

A ratio representing some part out of 100.

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Percents to DecimalsPercents to Decimals

55%

Drop % and move decimal point 2 places to the left.

=.55

38% =.38

14.5% =.145

.25% =.0025

%21

45 %.545 455.

Percents to FractionsPercents to Fractions

55%

Change to a decimal, then Read It, Write It, Reduce It

=.55

38% =.38

14.5% =.145

.25% =.0025

%21

45 %.545 455.

10055

2011

10038

5019

1000145

20029

1000025

4001

1000455

20091

Decimals to PercentsDecimals to Percents

Move the decimal point 2 places to the right and add %.

= 55%.55

= 38%.38

= 250%2.5

= .3%.003

Fractions to PercentsFractions to Percents

Change to a decimal and then to a percent.

43 75. %75

85

625. %.562

52

3 43. %340

Slide 1- 7Copyright © 2011 Pearson Education, Inc.

What is 7/8 as a percent?

a) 78%

b) 87%

c) 87.5%

d) 718%

3.2

Slide 1- 8Copyright © 2011 Pearson Education, Inc.

What is 7/8 as a percent?

a) 78%

b) 87%

c) 87.5%

d) 718%

3.2

Percent SentencesPercent Sentences

A percent of a whole is a part of the whole.

% multiply total(follows “of”)

part=

36% of 72 is what number?

.36 ∙ 72 = x

.36 (72) = x

25.92 = x

36% of 72 is 25.92.

Percent SentencesPercent Sentences

A percent of a whole is a part of the whole.

% multiply total part=

.42 ∙ x = 31.92

.42 x = 31.92

x = 76

42% of what number is 31.92?

42% of 76 is 31.92.

Percent SentencesPercent Sentences

x ∙ 63 = 56

63 x = 56

x = .8888888…

88.9% of 63 is 56.

What percent of 63 is 56?

x = 88.9%

Slide 1- 12Copyright © 2011 Pearson Education, Inc.

2.4% of 130 is what number?

a) 31.2

b) 3.12

c) 1.83

d) 0.18

3.2

Slide 1- 13Copyright © 2011 Pearson Education, Inc.

2.4% of 130 is what number?

a) 31.2

b) 3.12

c) 1.83

d) 0.18

3.2

Slide 1- 14Copyright © 2011 Pearson Education, Inc.

What percent of 48 is 51.84?

a) 93%

b) 98%

c) 108%

d) 109%

3.2

Slide 1- 15Copyright © 2011 Pearson Education, Inc.

What percent of 48 is 51.84?

a) 93%

b) 98%

c) 108%

d) 109%

3.2

Percent SentencesPercent Sentences

.06 x = 100

x = 1666.66666

Sentinel has 1,667 employees.

Percent ∙ whole = part

x = 1667

On Monday, January 17, 2012, the Morning Sentinel reported it planned to cut 100 full-time jobs in a bid to return to profitability. This is 6% of the newspaper’s workforce. How many employees does the Sentinel have?

Percent: 6% = .06Whole: x

Part: 100

Percent SentencesPercent Sentences

.07(570) = xx = 39.90

Total cost is $609.90.

Percent ∙ whole = part

What did we find?

Jamal purchases a new surfboard that costs $570. The sales tax is 7%, what is the total cost of the surfboard?

Percent: 7% = .07Whole: 570

Part: x

Sales tax.

Total cost = cost plus tax.903900570..

90609.