Phi - 1.618....The Golden Number

Phi ( = 1.618033988749895... ), most often pronounced fi like "fly," is simply an irrational number like pi ( p= 3.14159265358979... ), but one with many unusual mathematical properties. Unlike pi, which is a transcendental number, phi is the solution to a quadratic equation.

Phi in relation to Art:

As the Golden Section is found in the design and beauty of nature, it can also be used to achieve beauty and balance in the design of art. This is only a tool though, and not a rule, for composition.

The Golden Section was used extensively by Leonardo Da Vinci. Note how all the key dimensions of the room and the table in Da Vinci's "The Last Supper" were based on the Golden Section, which was known in the Renaissance period asThe Divine Proportion.