Proportion
A proportion is a statement that two ratios are equal. Proportions can be written as equivalent fractions or as equal ratios.
Examples
Equivalent fraction  :  =  
Equal ratio  :  1:2  =  7:14 
terms of a proportion
There are four terms of a proportion, often written as:  


The terms in the proportion are a, b, c, and d. The extremes are a and d, and the means are b and c. The product of the means and the product of the extremes are equal.  
Example  


Note that 2 × 7 = 1 × 14, showing that the two ratios are proportional. 
Related word proportional.
See also equal ratios, scale.