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 3 cookies cost $2.00, what is the cost of 1 cookie?

Back

The cost of 1 cookie is $2.00 ÷ 3 = $0.67.

Front

How do you calculate the total cost for multiple items?

Back

To calculate the total cost for multiple items, multiply the cost of one item by the number of items. For example, if 1 cookie costs $0.67, then 15 cookies cost $0.67 × 15 = $10.

Front

What is the formula to find the number of containers needed for a certain number of items?

Back

The formula is: Number of containers = Total items ÷ Items per container. For example, for 300 cupcakes with 36 per container, it is 300 ÷ 36 = 8.33, rounded to 9.

Front

How do you determine the number of servings needed based on the number of people?

Back

To determine the number of servings needed, divide the total number of people by the number of servings per unit. For example, for 180 kids and 1 tray for every 20 kids, it is 180 ÷ 20 = 9 trays.

Front

What is a ratio?

Back

A ratio is a comparison of two quantities by division, showing how many times one value contains or is contained within the other.

Front

How do you set up a proportion?

Back

To set up a proportion, create an equation that states two ratios are equal. For example, if 3 cookies cost $2.00, and you want to find the cost of 15 cookies, set it up as 3/2 = 15/x.

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.

Front

How can you use cross-multiplication to solve proportions?

Back

Cross-multiplication involves multiplying the numerator of one ratio by the denominator of the other ratio. For example, in 3/2 = 15/x, cross-multiply to get 3x = 30.