Proportions

Front

What is a proportion?

Back

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

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 have 120 customers in 8 hours, the unit rate is 120 ÷ 8 = 15 customers per hour.

Front

What is the formula for finding the price per unit?

Back

The formula for finding the price per unit is: Price per unit = Total price ÷ Number of units.

Front

If a recipe calls for 2 cups of flour for every 3 cups of sugar, what is the ratio of flour to sugar?

Back

The ratio of flour to sugar is 2:3.

Front

What is a ratio?

Back

A ratio is a comparison of two quantities by division.

Front

If 4 apples cost $2, how much do 10 apples cost?

Back

If 4 apples cost $2, then 10 apples cost $5 (using the unit rate: $2 ÷ 4 apples = $0.50 per apple, then $0.50 x 10 apples = $5).

Front

What is cross-multiplication?

Back

Cross-multiplication is a method used to solve proportions by multiplying the numerator of one ratio by the denominator of the other ratio.

Front

If a car travels 300 miles in 5 hours, what is its speed in miles per hour?

Back

The speed is 60 miles per hour (300 miles ÷ 5 hours = 60 miles per hour).

Front

What is the relationship between ratios and fractions?

Back

Ratios can be expressed as fractions, where the first quantity is the numerator and the second quantity is the denominator.

Front

If there are 3 red marbles for every 5 blue marbles, what is the total number of marbles if there are 15 blue marbles?

Back

If there are 15 blue marbles, there are 9 red marbles (3:5 ratio means for every 5 blue, there are 3 red; 15 blue ÷ 5 = 3, then 3 x 3 = 9 red).