1. SOLVING PROPORTIONS

2. proportion-  Words: an equation that shows that two ratios are equivalent =, b0,d0  Symbols  Symbols:

3. One way to determine whether two ratios form a proportion is to find their cross products. 18 If the cross products of two ratios are equal, then the ratios form a proportion. =

4. Property of Proportions  Words: the cross products of a proportion are equal  Symbols  Symbols: If =, then ad = bc.

5. If one value in a proportion is unknown, you can use equivalent fractions to solve the proportion. = z = 30 x 6

6. You can use proportions to make predictions. d = 120 prefer crest 8 out of 10 dentists prefer Crest. There are 150 dentists in a certain city. Predict how many of them prefer Crest. prefer Crest prefer Crest total total = x 15

7. = p = 1,404 people According to the results of a survey, 27 out of 50 people exercise regularly. Suppose there are 2600 people in a community. How many of these people can be expected to exercise regularly. exercise regularly exercise regularly total total x 52

8. If one value in a proportion is unknown, you can use cross products to solve the proportion. 4 4z z z = 102 = 20 = 4 z =5 =