1. Applications of Proportions

2. Sec. 1 Ratio and Rates A ratio is a comparison of two quantities by division. You can write a ratio in three different ways ArithmeticAlgebra

3. Simplify Ratios 1.Write it as a fraction 2.Simplify the fraction Ratios can be whole numbers

4. Simplify the following Ratios 50 seconds to 2 minutes 60 dogs to 15 cats 15 cats to 60 dogs 3 squares : 8 triangles 9 chairs : 12 desks

5. Rate A Rate is a specific ratio that compares quantities measured in different units – Miles per gallon – Feet per second – Newton's per square meter (Pascal's) – Force per volume Unit Rate is the rate for 1 unit of a given quantity

6. Example A car travels 120 miles on 4 gal. or gas. What is the rate? What is the unit Rate?

7. Try it! A cycling team finished a 200 lap race in 2 hrs. and 4 minutes, or 2.07 hrs. What is the unit rate of laps per hr.? About 96.6 laps/hr.

8. Try Another Find the unit rate for 52 deliveries in 8hrs 6.5 deliveries/hr.

9. In Real Life

10. Cereal The cost of a 20-Oz box of cereal is $4.29. A 12- Oz box of the same cereal is $3.59. Which is a better buy? Find the unit price of each and see which is cheaper.

11. Homework Pg. 162 8-30

12. Converting Units Look at the chart on pg. 166

13. Converting Units To convert units use a conversion factor, or multiply by a rate equal to 1 Sense conversion factors are equal to 1, multiplying by it does not change my value We call this process dimensional analysis

14. Dimensional Analysis How many feet are in 1.2 miles? Conversion Factor: there are 5,280 ft. in 1 mile. The ratio =1 Line up units to cancel

15. You can do it all in 1 step How many inches are in 1.2 miles? – I do not know how many inches are in a mile, but I do know how many inches are in a foot and how many feet are in a mile!

16. Set it Up You ran 0.15mi/min. Convert this to ft./s Use page 166 for conversion factors. Or my may already know some.

17. Solve it

18. Homework Pg. 169 7-24 use this method