Proportional Relationships

Front

What is a proportional relationship?

Back

A proportional relationship is a relationship between two quantities where the ratio of one quantity to the other quantity is constant.

Front

How do you find the unit rate?

Back

To find the unit rate, divide the quantity by the number of units. For example, if you read 280 pages in 4 hours, the unit rate is 280 ÷ 4 = 70 pages per hour.

Front

If 1 tray of tater tots is needed for every 20 kids, how many trays are needed for 180 kids?

Back

To find the number of trays needed, divide the number of kids by the number of kids per tray: 180 ÷ 20 = 9 trays.

Front

What is the ratio of boys to girls in a class with 3 boys for every 5 girls?

Back

The ratio of boys to girls is 3:5.

Front

If there are 70 girls in the 7th grade, how many boys are there if the ratio is 3 boys for every 5 girls?

Back

To find the number of boys, set up a proportion: 3/5 = x/70. Cross-multiply to find x = 42 boys.

Front

How do you calculate earnings per hour?

Back

To calculate earnings per hour, divide total earnings by the number of hours worked. For example, if Samantha earned $90 for 6 hours, her rate is $90 ÷ 6 = $15 per hour.

Front

If 1 container of frosting is needed for every 36 cupcakes, how many containers are needed for 300 cupcakes?

Back

To find the number of containers needed, divide the total cupcakes by the number of cupcakes per container: 300 ÷ 36 ≈ 8.33, which rounds to 9 containers.

Front

What is a ratio?

Back

A ratio is a comparison of two quantities that shows the relative size of one quantity to another.

Front

How can you express a proportional relationship using an equation?

Back

A proportional relationship can be expressed as y = kx, where k is the constant of proportionality.

Front

What does it mean if two quantities are directly proportional?

Back

If two quantities are directly proportional, as one quantity increases, the other quantity increases at a constant rate.