Area is the measure of the size of a surface, or of a region on such a surface. In analytical geometry, the letter "A" commonly denotes formulas for the determination of the areas of simple two-dimensional plane figures, while the letter "S" denotes formulas for the determination of surface areas of three-dimensional solids. The concept of area is dependent upon the more fundamental quantity of length. In ancient civilizations, people measured various distances by determining the number of times a standard unit of length must be added together to yield the distance in question. For example, the ancient Romans used the "stadium", with about 8.7 stadia equal to one statute mile, as their "reference" length to measure large distances. About 1,045 stadia (or 120 statute miles) added together equals the straight-line distance between the two Italian cities of Rome and Naples. In the same way, a surface is measured by denoting...