1. 2.1 Ratios and Proportions

2. Definitions Ratio an item in relation to another item (sometimes the same type of item, sometimes not, but there must be a difference of some kind) 1 to 3 or 1:3 or Proportion two equivalent ratios set equal to each other

3. Examples Write as a decimal.

4. Examples Write as a decimal.

5. Examples A live tree exhibit has 2 pine trees, 9 spruce trees, and 3 fir trees. What is the ratio of fir trees to trees in the exhibit?

6. Ratios in Cooking You have a recipe for pie crust that calls for 2 cups of flour, 1 cup of Crisco, and a half cup of water. The recipe makes a top and a bottom crust. You can get water from the tap, but you need to plan ahead for the flour and Crisco. What if you want to make enough crusts for 3 pies? What if you only need a bottom crust (for a meringue)?

7. Ratio Table Single Crust 1 pie3 pies20 pies Flour Crisco Algebra II

8. Raising a Ratio Fill out the table for the raising a ratio Algebra II Original Ratio DoubleTriplex 4x 5x 10x 32 4 7

9. Raising a Ratio Fill out the table for the raising a ratio Algebra II Original Ratio DoubleTriplex 4x 5x 10x 32 5 4

10. Reducing a Ratio Fill out the table for the reducing a ratio Algebra II Original Ratio Half One- third One- fourth One- tenth One- 20th One-50th 300 200

11. Reducing a Ratio Fill out the table for the reducing a ratio Algebra II Original Ratio Half One- third One- fourth One- tenth One- 20th One-50th 100 2000

12. Examples Solve for a

13. Examples A van travels 150 miles on 6 gallons of gas. Write and solve a proportion to determine the number of gallons needed to travel 500 miles.

14. Examples A survey indicated that 7 out of 8 doctors used brand X aspirin. If 4800 doctors were surveyed, how many used brand X?

15. Examples Solve the proportion

16. Examples Solve the proportion

17. Examples Solve the proportion

18. Assignment 2.1 Worksheet