1. + Percents & Percent of Change Algebra Monday Sept 21, 2015

2. + Warm Up

3. + Page of INB I CAN: use proportional relationships to solve multi-step problems related to percent increase and decrease Purpose: to use percents as a method of comparison Essential Understanding: problems involving percents can be solved using either proportions or the percent equation. If a percent is written as a fraction, a proportion can be used to solve a percent problem.

4. + Percents as a Proportion is = p of 100

5. + Calculating Simple Interest

6. + Your Turn You deposit $125 in a savings account that earns a simple interest rate of 1.75% per year. You earned a total of $8.75 in interest. For how long was your money in the bank? I = Prt

7. + Change Expressed as a Percent Percent of change – an amount of change as a percent of an original amount Percent increase – when the new number is more than the original amount Percent decrease = when the new amount is less than the original.

8. + Practice The average monthly precipitation for Chicago, IL peaks in June at 4.1 in. The average monthly precipitation in December is 2.8 in. What is the percent of change? In one year, the toll for passenger cars to use a tunnel rose from $3 to $3.50. What is the percent of change?

9. + Relative Error/Percent Error Solve: You thing that the distance between your house and a friends house is 5.5 mi. The actual distance is 4.75 mi. What is the percent error in your estimation?

10. + Percent of Change page of INB

11. + DOL 1. What percent of 70 is 21? 2. 75% of what number is 36? 3. What is 35% of 80? 4. Find the percent increase or decrease in each situation a) A hat originally costs $12 goes on sale for $9.50 b) You buy a CD for $10 and sell it for $8 c)A store buys glasses for $2, but sells them for $4.50.