SOLVING PROPORTIONS解决比例

Click to edit Master title style,*,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,SOLVING PROPORTIONS,proportion-,Words:,an equation that shows that two ratios are equivalent,=,b,0,d,0,Symbols,:,One way to determine whether two ratios form a proportion is to find their,cross products,.,18,18,If the cross products of two ratios are equal,then the ratios form a proportion.,=,Property of Proportions,Words:,the cross products of a proportion are equal,Symbols,:,If,=,then ad=bc.,If one value in a proportion is unknown,you can use equivalent fractions to solve the proportion.,=,z,=,30,x 6,x 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,x 15,=,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,x 52,If one value in a proportion is unknown,you can use cross products to solve the proportion.,4,4z,z,z,=,10,2,=,20,=,20,4,z,=,5,=,