3.2 Percents 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.

Review A ratio representing some part out of 100. Percent: A comparison of two quantities using a quotient (fraction). Proportion: Two ratios set equal. Cross Products: Cross products are equal. A ratio representing some part out of 100. Percent: 20% = 20 out of 100

55% =.55 Percents to Decimals Drop % and move decimal point 2 places to the left. 55% =.55 38% =.38 14.5% =.145 .25% =.0025

55% =.55 Percents to Fractions Change to a decimal, then Read It, Write It, Reduce It Tenths Hundredths Thousandths Ten Thousandths . 1 2 3 4 55% =.55 38% =.38 14.5% =.145 .25% =.0025

.55 = 55% Decimals to Percents Move the decimal point 2 places to the right and add %. .55 = 55% .38 = 38% 2.5 = 250% .003 = .3%

Fractions to Percents Change to a decimal and then to a percent.

What is 7/8 as a percent? a) 78% b) 87% c) 87.5% d) 718% 3.2 Copyright © 2011 Pearson Education, Inc. 3.2

What is 7/8 as a percent? a) 78% b) 87% c) 87.5% d) 718% 3.2 Copyright © 2011 Pearson Education, Inc. 3.2

Percent 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 Sentences A percent of a whole is a part of the whole. % multiply total = part 42% of what number is 31.92? ∙ x 31.92 .42 = .42 x = 31.92 x = 76 42% of 76 is 31.92.

Percent Sentences What percent of 63 is 56? x 56 ∙ 63 = 63 x = 56

2.4% of 130 is what number? a) 31.2 b) 3.12 c) 1.83 d) 0.18 3.2 Copyright © 2011 Pearson Education, Inc. 3.2

2.4% of 130 is what number? a) 31.2 b) 3.12 c) 1.83 d) 0.18 3.2 Copyright © 2011 Pearson Education, Inc. 3.2

What percent of 48 is 51.84? a) 93% b) 98% c) 108% d) 109% 3.2 Copyright © 2011 Pearson Education, Inc. 3.2

What percent of 48 is 51.84? a) 93% b) 98% c) 108% d) 109% 3.2 Copyright © 2011 Pearson Education, Inc. 3.2

Percent Sentences 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 ∙ whole = part Percent: 6% = .06 Whole: x .06 x = 100 Part: 100 x = 1666.66666 x = 1667 Sentinel has 1,667 employees.

Percent Sentences Jamal purchases a new surfboard that costs $570. The sales tax is 7%, what is the total cost of the surfboard? Percent ∙ whole = part Percent: 7% = .07 Whole: 570 .07(570) = x Part: x x = 39.90 What did we find? Sales tax. Total cost = cost plus tax. Total cost is $609.90.