Which of the following best defines a ratio?

Which of the following best defines a ratio?

• A. A number that can be expressed as a fraction.
• B. The sum of two numbers.
• C. A number sentence with an equals sign.
• D. A function relating two sets of data.

Answer: (A)

A ratio is a way to compare two quantities. Because comparing two amounts is the same as dividing the first by the second, a ratio can be written as a fraction. So representing a ratio as a fraction is natural and accurate. For example, if there are 3 red apples and 4 green apples, the ratio red to green is 3:4, which can be written as the fraction 3/4. The other ideas describe different concepts: adding numbers, an equation with an equals sign, or a rule linking two sets of data. Remember also that you can’t divide by zero when forming a ratio as a fraction.

A ratio is a way to compare two quantities. Because comparing two amounts is the same as dividing the first by the second, a ratio can be written as a fraction. So representing a ratio as a fraction is natural and accurate. For example, if there are 3 red apples and 4 green apples, the ratio red to green is 3:4, which can be written as the fraction 3/4. The other ideas describe different concepts: adding numbers, an equation with an equals sign, or a rule linking two sets of data. Remember also that you can’t divide by zero when forming a ratio as a fraction.