1. Lesson 5.2 Proportions
Students will be able use cross multiply to determine if the two ratios are equivalent.

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3. Proportions Example: 4 5 = 8 10
A proportion is an equation stating two ratios are equivalent (equal) or they have a constant rate.
Example: 4 5 = 8 10

4. Nonproportional Example: 4 5 ≠ 8 15
Relationships are nonproportional if the rates or ratios are not constant, equivalent.
Example: 4 5 ≠ 8 15

5. Cross Multiply Method
6 x 5 = 3 x 10
30 = 30

6. Proportions
Determine if the following are proportions. 1) 2)

7. Proportions
3 x 60 = 5 x 36
4 x 15 = 8 x 8
180 = 180 60 64
Yes, it is a proportion.
No, it is not a proportion.

8. Practice Problems 3 15 = 9 45 6 13 = 2 5 2 9 = 6 15 24 8 = 3 1
Determine if the two ratios are proportional
3 15 = 9 45
6 13 = 2 5
2 9 = 6 15
24 8 = 3 1

9. Solving Proportions 4 = 24 y 30 4(30) = 24y 120 = 24y 24 24 5 = y
5 = y
1. Cross Multiply
2. Solve for the variable.

10. Solving Proportions y 8 8(10) = 5y 80 = 5y 5 5 16 = y 10 = 5
16 = y
1. Cross Multiply
2. Solve for the variable