The golden ratio is formulated as in Euclid's Elements (s.-III) in a geometrical construction called Division of a segment in extreme and mean ratio . The idea is so simple and perfect: The whole is divided into two parts such that the proportional ratio between the smallest and largest, is equal to that between the highest and the total, ie the sum of both.
is starting segment AB. To apply the Golden Section is placed perpendicularly at one end (B) another segment that measures exactly half. It defines a right triangle with legs in proportion 1:2. However, the hypotenuse is subtracted from the lower leg (right arch) and the difference we bring to the segment AB with another bow, is the golden section of it. The lower part is the largest Bfi Afi like this is the sum AB.
