Using these measurements, write all possible ratios. Proportion From earliest times men have recognized the value of good proportions in architecture. The ancient Greeks and Romans followed certain mathematical ratios and proportions to attain order, unity and beauty in their buildings. Using fixed mathematical formulas they were able to establish a pleasing relationship among various parts of buildings that have been admired for generations. A proportion is an equation stating that two ratios are equal.
Every proportion has four terms .
The first and fourth terms are the extremes . The second and third terms are the means . In every proportion the product of the means equals the product of the extremes. The first equation below shows the order in which the terms of a proportion are written. Equations 2 and 3 demonstrate two ways in which a proportion may be written.