8 4 Percent of Increase and Decrease Percent

Percent change is the ratio of the amount of change to the original amount.

Finding Percent of Change • 20 is decreased to 11 – 20 – 11

Finding Percent of Change • 32 is increased to 67 – 68 – 32

Finding Percent of Change Word Problems: Your Turn • Angela is a famous architect.

• Prices at a local electronic store have changed over the years. By

Lesson Quiz for Student Response Systems 1. Identify the percent increase or decrease to

Lesson Quiz for Student Response Systems 2. Identify the percent increase or decrease to

Lesson Quiz for Student Response Systems 3. A winter coat originally sold for $75

Lesson Quiz Find each percent increase or decrease to the nearest percent. 1. from

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8. 4 Percent of Increase and Decrease

Percent change is the ratio of the amount of change to the original amount. percent change = amount of change x 100 original amount Percent increase describes how much the original amount increases. Percent decrease describes how much the original amount decreases.

Finding Percent of Change • 20 is decreased to 11 – 20 – 11 = 9 – Percent of Change = amount of change original amount – Percent of Change = 9 20 – Percent of Change ≈ 0. 45 – Percent of Change ≈ 45%

Finding Percent of Change • 32 is increased to 67 – 68 – 32 = 36 – Percent of Change = amount of change original amount – Percent of Change = 36 32 – Percent of Change ≈ 1. 125 – Percent of Change ≈ 112. 5%

Finding Percent of Change Word Problems: Your Turn • Angela is a famous architect. She made $90, 000 in 2004. In 2005 she made $120, 000. What is the percent of increase?

• Prices at a local electronic store have changed over the years. By what percent did the prices increase or decrease for the stereo system? • What percent did the prices change for the Cell phone? Item 1994 2004 Stereo System $98. 95 $135. 95 Cell Phone $245 $159

Lesson Quiz for Student Response Systems 1. Identify the percent increase or decrease to the nearest percent. from 23 to 29 A. 26% decrease B. 26% increase C. 32% decrease D. 32% increase

Lesson Quiz for Student Response Systems 2. Identify the percent increase or decrease to the nearest percent. from 1440 to 1220 A. 15% decrease B. 15% increase C. 28% decrease D. 28% increase

Lesson Quiz for Student Response Systems 3. A winter coat originally sold for $75 but is now on sale for 20% off. What is the sale price of the winter coat? A. $55 B. $60 C. $65 D. $70

Lesson Quiz Find each percent increase or decrease to the nearest percent. 1. from 12 to 15 25% increase 2. from 1625 to 1400 14% decrease 3. from 37 to 125 238% increase 4. from 1. 25 to 0. 85 32% decrease 5. A computer game originally sold for $40 but is now on sale for 30% off. What is the sale price of the computer game? $28