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

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 = 27 percent of change =  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%

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 – 41 = 51 Percent of change = 41  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

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 = 25 percent of change =  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%

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 – 37 = 19 Percent of change = 37  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

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

6-4 Percent of Change The regular price of a bicycle helmet is $ 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% · = d 0.20 · = d = 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.

6-4 Percent of Change The regular price of a bicycle helmet is $ 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

6-4 Percent of Change The regular price of a computer game is $ 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% · = d 0.15 · = d = 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.

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 $ $49.88 – $7.48 = $42.40 The regular price of a computer game is $ It is on sale for 15% off. What is the sales price?

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% · = n 1.10 · = n = n Step 2: Find the selling price. wholesale price + amount of increase = retail price $ $13.86 = $26.46 The retail price of the hand-painted T-shirts is $26.46 each. Write the percent as a decimal. Multiply.

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 $ $8.75 = $15.75

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

6-4 Percent of Change Lesson Quiz Find each percent of change is increased to is increased to is decreased to 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

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

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

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

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

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