1. 6-4 Percent of Change Percent of change = amount of change original amount

2. 6-4 Percent of Change Find the percent of change. Round answers to the nearest tenth of a percent, if necessary. Additional Example 1A: Finding Percent of Change 65 is decreased to 38. 65 – 38 = 27 percent of change = 27 65  0.4153846 The percent of decrease is about 41.5%. Find the amount of change. Substitute values into formula. Divide. Write as a percent. Round. When a number is decreased, subtract the new amount from the original amount to find the amount of change. Helpful Hint  41.5%

3. 6-4 Percent of Change Find the percent of change. Round answers to the nearest tenth of a percent, if necessary. Additional Example 1B: Finding Percent of Change 41 is increased to 92. 92 – 41 = 51 Percent of change = 41  1.2439 The percent of increase is about 124.4% Find the amount of change. Substitute values into formula. Divide. Write as a percent. Round.  124.4% 51 When a number is increased, subtract the original amount from the new amount. Helpful Hint

4. 6-4 Percent of Change Find the percent of change. Round answers to the nearest tenth of a percent, if necessary. Check It Out: Example 1A 70 is decreased to 45. 70 – 45 = 25 percent of change = 25 70  0.35714 The percent of decrease is about 35.7%. Find the amount of change. Substitute values into formula. Divide. Write as a percent. Round.  35.7%

5. 6-4 Percent of Change Find the percent of change. Round answers to the nearest tenth of a percent, if necessary. Check It Out: Example 1B 37 is increased to 56. 56 – 37 = 19 Percent of change = 37  0.51351 The percent of increase is about 51.4% Find the amount of change. Substitute values into formula. Divide. Write as a percent. Round.  51.4% 19

6. 6-4 Percent of Change When you know the percent of change, you can use an equation to find the actual amount of change.

7. 6-4 Percent of Change The regular price of a bicycle helmet is $42.99. It is on sale for 20% off. What is the sales price? Additional Example 2: Using Percent of Change Step 1: Find the amount of the discount d. 20% · 42.99 = d 0.20 · 42.99 = d 8.598 = d $8.60  d The amount of the discount is $8.60. Think: 20% of $42.99 is what number? Write the percent as a decimal. Multiply. Round to the nearest cent.

8. 6-4 Percent of Change The regular price of a bicycle helmet is $42.99. It is on sale for 20% off. What is the sales price? Additional Example 2 Continued Step 2: Find the sale price. regular price – amount of discount = sales price The sale price is $34.39 $42.99 – $8.60 = $34.39

9. 6-4 Percent of Change The regular price of a computer game is $49.88. It is on sale for 15% off. What is the sales price? Check It Out: Example 2 Step 1: Find the amount of the discount d. 15% · 49.88 = d 0.15 · 49.88 = d 7.482 = d $7.48  d The amount of the discount is $7.48. Think: 15% of $49.88 is what number? Write the percent as a decimal. Multiply. Round to the nearest cent.

10. 6-4 Percent of Change Check It Out: Example 2 Continued Step 2: Find the sale price. regular price – amount of discount = sales price The sale price is $42.40. $49.88 – $7.48 = $42.40 The regular price of a computer game is $49.88. It is on sale for 15% off. What is the sales price?

11. 6-4 Percent of Change A boutique buys hand-painted T-shirts for $12.60 each and sells them at a 110% increase in price. What is the retail price of the T-shirts? Additional Example 3: Business Application Step 1: Find the actual amount of increase. Think: 110% of $12.60 is what number? 110% · 12.60 = n 1.10 · 12.60 = n 13.86 = n Step 2: Find the selling price. wholesale price + amount of increase = retail price $12.60 + $13.86 = $26.46 The retail price of the hand-painted T-shirts is $26.46 each. Write the percent as a decimal. Multiply.

12. 6-4 Percent of Change Check It Out: Example 3 William makes T-shirts for $7.00 each and sells them after a price increase of 125%. What is the retail price of the T-shirts? Step 1: Find the actual amount of increase. Think: 125% of $7.00 is what number? 125% · 7.00 = n 1.25 · 7.00 = n 8.75 = n Step 2: Find the selling price. The retail price of the T-shirts is $15.75 each. Write the percent as a decimal. Multiply. wholesale price + amount of increase = retail price $7.00 + $8.75 = $15.75

13. 6-4 Percent of Change Standard Lesson Quiz Lesson Quizzes Lesson Quiz for Student Response Systems

14. 6-4 Percent of Change Lesson Quiz Find each percent of change. 1. 10 is increased to 12. 2. 25 is increased to 45. 3. 10 is decreased to 1. 4. The regular price of a coat is $120. It is on sale for 25% off. What is the sale price? 5. A backpack that sells for $42 is on sale for 25% off. Find the sale price. 80% 20% 90% $90 $31.50

15. 6-4 Percent of Change 1.Identify the percent of change. 20 is increased to 22. A. 10% B. 20% C. 30% D. 40% Lesson Quiz for Student Response Systems

16. 6-4 Percent of Change 2.Identify the percent of change. 30 is increased to 54. A. 30% B. 54% C. 75% D. 80% Lesson Quiz for Student Response Systems

17. 6-4 Percent of Change 3.Identify the percent of change. 15 is decreased to 3. A. 80% B. 75% C. 60% D. 50% Lesson Quiz for Student Response Systems

18. 6-4 Percent of Change 4.The regular price of a camera is $140. A store offers 30% off on cameras. At this discounted rate, what is the sale price of a camera? A. $110 B. $105 C. $98 D. $42 Lesson Quiz for Student Response Systems

19. 6-4 Percent of Change 5.A camcorder that sells for $256 is on sale for 30% off. Identify the sale price. A. $195.60 B. $179.20 C. $106.40 D. $76.80 Lesson Quiz for Student Response Systems