1. Lesson 4-3 Proportions and Percent Equations Objective: To use proportions when solving percent problems and to write and solve percent problems.

2. …and why? One example of a real world connection is to calculate the total water supply of the USA. One example of a real world connection is to calculate the total water supply of the USA.

3. PERCENT REMINDER A percent is a ratio comparing a number to 100. A percent is a ratio comparing a number to 100. USE THE FOLLOWING PROPORTION FOR SOLVING PERCENT PROBLEMS: USE THE FOLLOWING PROPORTION FOR SOLVING PERCENT PROBLEMS: ‘ N* ‘ = ‘ part ‘ 100 whole 100 whole *N/100 is the percent.

4. Examples 1 & 2, page 197 Finding the percent. Finding the percent. Ex. 1) What percent of 40 is 30? Finding the part. Finding the part. Ex. 2) Find 30% of 40.

5. Example 3, page 198 Ex. 3 – Charlie worked 31.5 hours at a hospital as a volunteer. This represents 87.5% of the school’s requirement for community service. How many hours does his school require for community service? Ex. 3 – Charlie worked 31.5 hours at a hospital as a volunteer. This represents 87.5% of the school’s requirement for community service. How many hours does his school require for community service?

6. Percent Equations Key Words Key Words “What …” is the unknown. Use x. “What …” is the unknown. Use x. “Is” means =. “Is” means =. “Of” means to multiply. “Of” means to multiply.

7. Ex. 4, page 198 Write and solve a percent equation. A) What is 85% of 320? A) What is 85% of 320? B) 393 is 60% of what number? B) 393 is 60% of what number?

8. Example 5, page 199 Find each number or percent. Ex. 5a) 105 is 125% of what number. Ex. 5a) 105 is 125% of what number. Ex. 5b) What percent of 320 is 1.6? Ex. 5b) What percent of 320 is 1.6? Ex. 5c) 640 is what percent of 32? Ex. 5c) 640 is what percent of 32? Ex. 5d) 0.13% of what number is 3000? Ex. 5d) 0.13% of what number is 3000?

9. Using Estimation, page 199 Use fractions to estimate. Ex. 6a) 49% of 280 is what number? Ex. 6a) 49% of 280 is what number? Ex. 6b) What is 65% of 334? Ex. 6b) What is 65% of 334? Ex. 6c) What is 74.2% of 44? Ex. 6c) What is 74.2% of 44? Ex. 6d) 11% of 521 is what number? Ex. 6d) 11% of 521 is what number?

10. Example 7, page 200 A store advertises sneakers on sale for 33% off. The original price of sneakers is $56. A) Estimate the amount the sneakers have been marked down. A) Estimate the amount the sneakers have been marked down. B) Estimate the sale price of the sneakers. B) Estimate the sale price of the sneakers.

11. SUMMARY TO SOLVE PERCENT PROBLEMS either Use a percent proportion Use a percent proportion N/100 = part/whole Or A percent equation where A percent equation where “is” means = and “of” means to multiply.

12. Assignment P. 200 1 – 57 odd; 61 – 73 odd