Solving 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

If a car travels 120 miles in 3 hours, what is its speed in miles per hour?

Back

The speed is 40 miles per hour (120 miles ÷ 3 hours).

Front

If a car travels at a constant speed of 40 miles per hour, how long will it take to travel 200 miles?

Back

It will take 5 hours (200 miles ÷ 40 miles per hour).

Front

What is the relationship between the number of ice cream cones and brownies sold if there are 5 cones for every 3 brownies?

Back

The ratio of ice cream cones to brownies is 5:3.

Front

If there are 24 brownies sold, how many ice cream cones are sold?

Back

40 ice cream cones (5/3 = x/24, x = 40).

Front

How do you find the cost per slice of pizza if a pizza with 8 slices costs $12?

Back

Divide the total cost by the number of slices: $12 ÷ 8 = $1.50 per slice.

Front

If 4 big water bottles hold 8 gallons, how much does 1 big water bottle hold?

Back

Each big water bottle holds 2 gallons (8 gallons ÷ 4 bottles).

Front

How much water can 3 big water bottles hold if each holds 2 gallons?

Back

6 gallons (3 bottles × 2 gallons per bottle).

Front

What is cross-multiplication in solving proportions?

Back

Cross-multiplication involves multiplying the numerator of one ratio by the denominator of the other ratio.