ABSTRACT
A ratio is the established relationship between two numbers. A proportion exists when the value of one ratio is equal to the value of a second ratio. For example, the value of 1/2 is equal to the value of 4/8. Therefore, these two ratios are in proportion. There are three methods that may be used to determine if two ratios are in proportion—division, means and extremes, and cross multiplication. When two ratios are written as fractions, cross multiplication can be used to determine if the two ratios are proportionate. A proportion is defined as two equal ratios. However, a proportion could also be thought of as two equivalent fractions. In other words, the numerator and denominator of the first fraction can be multiplied or divided by some number in order to obtain the second fraction.
