2. Main Idea and New Vocabulary Key Concept: Proportion
Example 1: Write and Solve a Proportion
Example 2: Make Predictions
Example 3: Write and Use an Equation
Lesson Menu

3. Use proportions to solve problems.
equivalent ratios
proportion
cross products
Main Idea/Vocabulary

4. Key Concept

5. Write and Solve a Proportion
CLOTHING Melvin can decorate 8 T-shirts in 3 hours. Write and solve a proportion to find the time it will take him to decorate 20 T-shirts at this rate.
Write a proportion. Let h represent the time in hours.
8  h = 3 ● 20 Find the cross products.
8h = 60 Multiply.
Example 1

6. Write and Solve a Proportion
Divide each side by 8.
h = 7.5
Answer: It will take Melvin 7.5 hours to decorate 20 T-shirts.
Example 1

7. JEWELRY Roxanne can make 5 bracelets in 2 hours
JEWELRY Roxanne can make 5 bracelets in 2 hours. Write and solve a proportion to find the time it will take her to make 40 bracelets at this rate. A. B. C. D.
Example 1 CYP

8. Write a proportion. Let c represent the cups of flour needed.
Make Predictions
COOKING A recipe serves 10 people and calls for 3 cups of flour. If you want to make the recipe for 15 people, how many cups of flour should you use?
Write a proportion. Let c represent the cups of flour needed.
Example 2

9. 10  c = 3 ● 15 Find the cross products. 10c = 45 Multiply.
Make Predictions
10  c = 3 ● 15 Find the cross products.
10c = 45 Multiply.
Divide each side by 8.
c = 4.5
Answer: You should use 4.5 cups of flour.
Example 2

10. BIRDHOUSES Brooke needs to use 25 nails for every 5 birdhouses that she builds. How many nails will she need to make 8 birdhouses?
A. 200 nails
B. 40 nails
C. 16 nails
D. 1.6 nails
Example 2 CYP

11. Write and Use an Equation
FOOD Haley bought 4 pounds of tomatoes for $ Write an equation relating the cost to the number of pounds of tomatoes. How much would Haley pay for 6 pounds at this same rate? for 10 pounds?
Find the unit rate between cost and pounds of tomatoes.
Example 3

12. Write and Use an Equation
Find the cost of 6 pounds sold at the same rate.
c = 2.99p Write the equation.
c = 2.99(6) Replace p with 6.
c = Multiply.
The cost for 6 pounds of tomatoes is $17.94.
Example 3

13. Write and Use an Equation
Find the cost of 10 pounds sold at the same rate.
c = 2.99p Write the equation.
c = 2.99(10) Replace p with 100.
c = Multiply.
The cost for 10 pounds of tomatoes is $29.90.
Answer: The cost for 6 pounds of tomatoes is $17.94 and the cost for 10 pounds is $29.90.
Example 3

14. MOVIES Jeremy bought 5 movie tickets for $53. 75
MOVIES Jeremy bought 5 movie tickets for $ Write an equation relating the cost to the number of tickets. How much would Haley pay for 7 movie tickets at this same rate?
A. c = 5t; $38.39
B. c = 7.68; $75.25
C. c = 10.75t; $75.25
D. c = 48.75t; $341.25
Example 3 CYP