Practice Proportions in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

An equation stating that two ratios are equal, used to find an unknown when three of the four values are known.

If 2 candies cost \$1, then 4 candies cost \$2β€”same proportion.

Showing a random 20 of 50 problems.

Example 1

medium
On a map, 1 inch represents 25 miles. What distance is shown by 4.5 inches?

Example 2

easy
In the proportion ab=cd\frac{a}{b} = \frac{c}{d}, which equation expresses the cross-product rule?

Example 3

medium
3 liters of paint cover 24 square meters. How many liters cover 40 square meters?

Example 4

medium
If yy is directly proportional to xx and y=18y = 18 when x=4x = 4, find yy when x=10x = 10.

Example 5

challenge
If ab=cd\frac{a}{b} = \frac{c}{d}, show that a+cb+d=ab\frac{a + c}{b + d} = \frac{a}{b} (assuming b+d≠0b + d \neq 0).

Example 6

easy
Solve: 37=9x\frac{3}{7} = \frac{9}{x}.

Example 7

easy
Solve x5=615\frac{x}{5}=\frac{6}{15}.

Example 8

medium
A car uses 8 gallons of gas to travel 224 miles. How many gallons are needed for 350 miles at the same rate?

Example 9

easy
Solve the proportion 34=x8\frac{3}{4}=\frac{x}{8}.

Example 10

medium
A blueprint uses 2 inches for every 5 feet. How many feet does 7 inches represent?

Example 11

hard
Three pumps fill a tank in 12 hours. How long would 5 pumps take, working at the same rate?

Example 12

easy
Solve 46=x9\frac{4}{6}=\frac{x}{9}.

Example 13

medium
Solve the proportion: x12=58\frac{x}{12} = \frac{5}{8}.

Example 14

easy
A map scale is 1Β cm50Β km\frac{1\text{ cm}}{50\text{ km}}. How many km does 3 cm represent?

Example 15

medium
A recipe calls for 3 cups of sugar to 8 cups of flour. If you have 20 cups of flour, how many cups of sugar do you need?

Example 16

easy
If 6 pencils cost \$1.50, how much do 2 pencils cost at the same rate?

Example 17

medium
If 5 notebooks cost $8.75\$8.75, how much do 12 notebooks cost?

Example 18

easy
Are 46\frac{4}{6} and 1015\frac{10}{15} equal?

Example 19

medium
If 4 workers build a wall in the same time that the ratio predicts, and 4 workers lay 200 bricks, how many bricks do 10 workers lay at the same rate?

Example 20

easy
If 2 pencils cost \$1, how much do 4 pencils cost at the same rate?