Proportions

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal.

Front

How do you solve for a variable in a proportion?

Back

To solve for a variable in a proportion, cross-multiply and then isolate the variable.

Front

If 13 out of 20 homes have a personal computer, what is the ratio of homes with computers to total homes?

Back

The ratio is 13:20.

Front

What is the cross-multiplication method?

Back

The cross-multiplication method involves multiplying the numerator of one ratio by the denominator of the other ratio.

Front

If a recipe calls for 1.5 cups of milk for every 3 cups of flour, what is the proportion of milk to flour?

Back

The proportion is 1.5:3 or simplified, 1:2.

Front

How do you find an equivalent ratio?

Back

To find an equivalent ratio, multiply or divide both terms of the ratio by the same non-zero number.

Front

What is the value of k if 1/5 = k/25?

Back

k = 5.

Front

If a car travels 60 miles in 1 hour, how far will it travel in 3 hours?

Back

180 miles.

Front

What is the formula for finding a missing value in a proportion?

Back

If a/b = c/d, then ad = bc.

Front

If 4/5 of a class are girls, what fraction of the class are boys?

Back

1/5 of the class are boys.