Golden section golden mean golden ratio

A theory of proportion, it has been used for centuries by artists in painting compositions and is based on proportions found in nature. It is a division of sections whereby the smaller one is the same proportion to the larger as the larger is to the whole work, a ratio of of approximately 5 to 8: A(the whole) is to B (the larger section) as B is to C (the smaller section). The name Golden Section was first used in the nineteenth century, but the proportion itself dates back to the work of the Greek mathematician, Euclid. In the early fifteenth century the Italian mathematician, Luca Pacioli, wrote a book on the subject called "Divina Proportione", which was illustrated by Leonardo da Vinci and used in his "Last Supper" composition. This influential work led to the widespread use of the Golden Section by many Renaissance and later artists and architects. Source: Wikipedia: http://www.goldennumber.net/goldsect.htm