The golden ratio is an irrational mathematical constant, approximately 1.6180339887. Other names frequently used for the golden ratio are the golden section and golden mean. Other terms encountered include extreme and mean ratio,medial section, divine proportion, divine section, golden proportion, golden cut,golden number, and mean of Phidias.
At least since the Renaissance, many artists and architects have proportioned their works to approximate the golden ratio—especially in the form of the golden rectangle, in which the ratio of the longer side to the shorter is the golden ratio—believing this proportion to be aesthetically pleasing. Mathematicians have studied the golden ratio because of its unique and interesting properties but I am simply fascinated with it’s history and use in design.