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1,001 Basic Math and Pre-Algebra Practice Problems For Dummies by Mark Zegarelli

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Chapter 12

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:

check.png Knowing how ratios and fractions are related

check.png Using ratios to set up a proportional equation

check.png Solving word problems using proportions

What to Watch Out For

Here are a few tips for sorting out problems that involve ratios and proportions:

check.png 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 9781118446454-eq12001.eps.

A proportion is an equation that includes two ratios set equal to each other. For example:

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