Proportions

Front

What is a proportion?

Back

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

Front

How do you solve a proportion?

Back

To solve a proportion, cross-multiply the two ratios and set the products equal to each other.

Front

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

Back

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

Front

If 3 apples cost $6, how much do 5 apples cost?

Back

$10 (Set up the proportion: 3/6 = 5/x, cross-multiply to find x).

Front

What is a ratio?

Back

A ratio is a comparison of two quantities by division.

Front

If the ratio of boys to girls is 4 to 5 and there are 20 boys, how many girls are there?

Back

25 girls (Set up the proportion: 4/5 = 20/x, cross-multiply to find x).

Front

What is the relationship between ratios and proportions?

Back

Ratios compare two quantities, while proportions show that two ratios are equal.

Front

If a recipe calls for 2 cups of sugar for 4 cups of flour, how much sugar is needed for 10 cups of flour?

Back

5 cups of sugar (Set up the proportion: 2/4 = x/10, cross-multiply to find x).

Front

What is the unit rate?

Back

The unit rate is a comparison of two different quantities when they are combined together, expressed as a quantity of one.

Front

If a car travels 150 miles in 3 hours, what is the unit rate in miles per hour?

Back

50 miles per hour (150 miles ÷ 3 hours).