Ratios and Proportions
A ratio is a comparison between two numbers. A proportion is a simple and useful equation based on a ratio. Ratios and proportions are closely related to fractions. In most cases, changing a ratio into a fraction will help you apply your knowledge of fractions to solve the problem you’re facing.
The Problems You’ll Work On
The following are a few examples of the types of problems you face in this chapter:
Knowing how ratios and fractions are related
Using ratios to set up a proportional equation
Solving word problems using proportions
What to Watch Out For
Here are a few tips for sorting out problems that involve ratios and proportions:
Ratios are easier to work with as fractions. Change a ratio to a fraction by putting the first number in the numerator and the second number in the denominator. For example, the ratio 2:5 is equivalent to the fraction .
A proportion is an equation that includes two ratios set equal to each other. For example: