1. Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall. Chapter 5 Ratio, Proportion, and Measurement

2. Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall. 5.2 Proportions

3. 33 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall. Writing Proportions A proportion is a statement that two ratios or rates are equal. For example, is a proportion. We can read this as “5 is to 6 as 10 is to 12.”

4. 44 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall. Example Write the statement 12 diamonds is to 15 rubies as 4 diamonds is to 5 rubies as a proportion.

5. 55 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall. Determining Whether Proportions are True

6. 66 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall. Example Is a true proportion? Determine the cross products. Since the cross products are not equal. The proportion is false.

7. 77 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall. Finding Unknown Numbers in Proportions When one number of a proportion is unknown, we can use cross products to find the unknown numbers. Finding an Unknown Value n in a Proportion Step 1: Set the cross products equal to each other. Step 2: Divide the number not multiplied by n by the number multiplied by n.

8. 88 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall. Example Find the value of the unknown number n.

9. 99 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall. Example Find the value of the unknown number n.