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Article: Ratio, Rate, and Proportion
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CopyrightCOPYRIGHT 2002 The Gale Group Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Ratio, Rate, and Proportion
If there are seven boys and twelve girls in a class, then the ratio of boys to girls can be expressed as 7 to 12, , or 7:12. A ratio compares the size, or magnitude, of two numbers. Two other related concepts, rate and proportion, together with ratio, are used for solving many real-world problems that involve comparing different quantities.
Calculating Ratios
Suppose a parking garage contains six blue cars and two green cars. The ratio of blue cars to green cars can be expressed as a fraction . If the two green cars leave the garage, then there are zero green cars and the ratio becomes . Division by zero, however, is not defined, so this form of the ratio is ...