1. Solving Proportions

2. EXAMPLE 1 Solve the proportion 4 12 20 x =. Solving Proportions METHOD - Use equivalent ratios. 4 12 20 x = 4 5 12 5 12 X 5 = 60, so x = 60. The solution is 60. ANSWER

3. GUIDED PRACTICE n = 1 n 4 6 24 = 1. k = 2 25 10 5 k = 2. ANSWER n 4 6 24 = 25 10 5 k = Solve the proportion using equivalent ratios.

4. GUIDED PRACTICE x = 55 30 x 6 11 = 3. s = 30 10 4 s 12 = 4. ANSWER Solve the proportion using equivalent ratios. 30 x 6 11 = 10 4 s 12 =

5. EXAMPLE 2 Boating: You are on a riverboat trip. You travel 5 miles in 3 hours. At that same rate, how long will it take you to travel 20 miles? SOLUTION Use a proportion. Let t represent the total time, in hours, of the 2 0 mile trip. Write a verbal model. Distance traveled Time traveled Total distance Total time = Substitute values. 5 mi 3 h 20 mi 12 h = Solving Using a Verbal Model Solve the proportion 5 mi 3 h 20 mi t h =

6. GUIDED PRACTICE 5.What If? In Example 2, suppose you travel 4 miles in 2 hours. At that same rate, how long will it take you to travel 20 miles? 4 mi 2 h 20 mi t h = ANSWER 4 2 20 t = t = 10 h for Example 2

7. Proportions around us SCHOOL The ratio of boys to girls in history class is 4 to 5. How many girls are in the class if there are 12 boys in the class?

8. Proportions at work FACTORIES A factory produces 6 motorcycles in 9 hours. Write a proportion and solve it to find how many hours it takes to produce16 motorcycles.

9. Proportions at home COOKING A recipe that will make 3 pies calls for 7 cups of flour. Write a proportion and solve it to find how many pies can be made with 28 cups of flour.

10. Proportions in sports BASKETBALL The Lakewood Wildcats won 5 of their first 7 games this year. There are 28 games in the season. About how many games would you expect the Wildcats to win this season?