In math a proportion is a way of showing that two fractions are equal to each other; for example, 1/2 = 2/4. Common problems using proportions involve situations where three of the four numbers in the proportion are known, and one must calculate the missing value.
A common example of proportions involves calculating percentages. A football analyst who wants to know how many games a team must win in a season to have an 75 percent win rate uses the following proportion: x/16 = 75/100. To find the answer, multiply across the proportion to remove the fractions and reach a simple algebraic equation: 100x = 1200, or x = 12. This shows that a team must win 12 of 16 games to reach a 75 percent win rate.