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
dc
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.
bcad
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.