1. Chapter 3.1 Percent Proportion

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3. a.If 52 out of 100 chickens are hens, then 52 per 100 or, or 52% of the chickens are hens. b. If a person pays a tax of $9 on every $100 of purchases, then the tax rate is $9 per $100. The ratio is and the percent of tax is 9%. Parallel Example 1 Understanding Percent 3

4. Write each percent as a decimal. Parallel Example 2 Writing Percents as Decimals 4 a.32% p% = p ÷ 100 32% = 32 ÷ 100 = 0.32 b.78% 78% = 78 ÷ 100 = 0.78 c.93.4% 93.4% = 93.4 ÷ 100 = 0.934 d.200% 200% = 200 ÷ 100 = 2.00

5. Write each percent as a decimal by moving the decimal point two places to the left. a. 23% 23.% 0.23 23% = 0.23 b. 180% 180.% = Parallel Example 3 Writing Percents as Decimals by Moving the Decimal Point 5 180.% = 1.80 or 1.8 Decimal point starts at far right side Percent sign is dropped (Step 1) Decimal point is moved two places to the left. (Step 2)

6. Write each percent as a decimal by moving the decimal point two places to the left. c. 3.2%.032 0 is attached so the decimal point can be moved two places to the left. d. 0.7% 0.7% = Parallel Example 3 Writing Percents as Decimals by Moving the Decimal Point 6 0.007 Two zeros are attached so the decimal point can be moved two places to the left.

7. Write each decimal as a percent by moving the decimal point two places to the right. a. 0.26 0.26 Decimal point is moved two places to the right. 0.26 = 26% b. 0.376 Parallel Example 4 Writing Decimals as Percents by Moving the Decimal Point 7 = 37.6% Percent sign is attached and decimal point is not written with whole number percents.

8. = 3.40 Write each decimal as a percent by moving the decimal point two places to the right. c. 1.83 d. 3.4 3.4 = 340% e. 5 5. = 5.00 so 5 = 500% Parallel Example 4 Writing Decimals as Percents by Moving the Decimal Point 8 Attach % sign. 0 is attached so the decimal point can be moved two places to the right. = 183% Two zeros are attached so the decimal point can be moved two places to the right. Attach % sign.

9. Write each fraction as a percent. Round to the nearest tenth if necessary. Parallel Example 3 continued Writing Fractions as Percents 9 b. Write as a percent by solving a proportion. Find cross products and show that they are equivalent. 1 1 So,

10. Write each fraction as a percent. Round to the nearest tenth if necessary. Parallel Example 3 continued Writing Fractions as Percents 10 c. Start with a proportion. Find cross products and show that they are equivalent. 1 1 So,

11. 11 The percent proportion can be used to solve problems.

12. Use the percent proportion and solve for the unknown value. Let x represent the unknown. a. part = 20, percent = 80; find the whole. Find the cross products. Show that the cross products are equivalent. Parallel Example 1 Using the Percent Proportion 12 x 80 20 100

13. Use the percent proportion and solve for the unknown value. Let x represent the unknown. b. part = 12, whole = 40; find the percent. The percent is written as 30%. Parallel Example 1 Using the Percent Proportion 13 Write the fraction in lowest terms. Find the cross products. Divide both sides by 10.

14. Use the percent proportion and solve for the unknown value. Let x represent the unknown. c. whole = 120, percent = 90; find the part. The part is 108. Parallel Example 1 Using the Percent Proportion 14 Write the fraction in lowest terms. Find the cross products. Divide both sides by 10.

15. Solve each problem. What is 6% of 80? 16% of what number is 12? What percent of 75 is 90? Solution: Slide 2.6-19 Solving Percent Equations CLASSROOM EXAMPLE 8

16. Solution: Let x = the number of possible points on the test. There were 40 possible points on the test. Mark scored 34 points on a test, which was 85% of the possible points. How many possible points were on the test? Slide 2.6-20 Solving Applied Percent Problems CLASSROOM EXAMPLE 9

17. Parallel Example 1 Solving for Sales Tax Slide 6.6- 17 Sam’s Sporting Goods sells a tent for $189. If the sales tax is 5%, how much tax is paid? What is the total cost of the tent?

18. Parallel Example 2 Finding the Sales Tax Rate Slide 6.6- 18 The sales tax on a $580 recliner is $46.40. Find the rate of the sales tax.

19. Parallel Example 3 Determining the Amount of Commission Slide 6.6- 19 Caleb Martinez had exercise equipment sales of $12,700 while working part-time last month. If his commission rate is 9%, find the amount of his commission. Caleb earned $1143.

20. Parallel Example 5 Finding a Sale Price Slide 6.6- 20 Art Designs has a painting with an original price of $620 on sale for 15% off. Find the sale price of the painting. $93 was slashed from the original amount. 620-93=527 The final sale price is $527

21. Slide 6.6- 21 We are often interested in looking at increases or decreases in sales, production, population, and many other items. Use the following steps to find the percent of increase. Finding the Percent of Increase Step 1Use subtraction to find the amount of increase. Step 2Use the percent proportion to find the percent of increase.

22. Parallel Example 6 Finding the Percent of Increase Slide 6.6- 22 A budget had an increase from $19,600 last year to $40,060 this year. Find the percent of increase. The percent of increase is 104.4%.

23. Slide 6.6- 23 Finding the Percent of Decrease Step 1Use subtraction to find the amount of decrease. Step 2Use the percent proportion to find the percent of decrease.

24. Parallel Example 7 Finding the Percent of Decrease Slide 6.6- 24 The number of minutes Rita used on her cell phone dropped this month to 798 from 840 last month. Find the percent of decease. The percent of decrease is 5%.

25. HW 3.1 1-26 Slide 1- 25