The name rational is based on the word ‘ratio.’ A ratio is a comparison of two or more numbers and is often written as a fraction. A number is considered a rational number if it can be written as one integer divided by another integer. Sometimes this is referred to as a simple fraction. The natural numbers, whole numbers, and integers, like 5, are all part of the set of rational numbers as well because they can be written as fractions. Euclid (c. 325-265 BC), of Alexandria, probably a student at the Academy founded by Plato, wrote a treatise in 13 books (chapters), titled The Elements of Geometry. The fundamental concepts of geometry deal with lines, points, planes, shapes line segments, midpoints, etc. There are certain formulas available for measuring the geometry concepts.