The golden ratio, also known as the divine proportion, golden mean, or golden section, is a number often encountered when taking the ratios of distances in simple geometric figures such as the pentagon, pentagram, decag on and dodecahedron. It is denoted , or sometimes .
Related to this, is the Fibonacci sequence, which when arranged in a spiral it is said to have, in art, the perfect proportion, as it keeps the golden ratio.: http://en.wikipedia. org/wiki/Fibonacci_sequence