The Golden Section is a ratio based on a phi (Φ).
The Golden Section is also known as the Golden Mean, Golden Ratio and Divine Proportion. It is a ratio or proportion defined by the number phi = (1.618033988749895).

The ratio of the whole line (A) to the large segment (B) is the same as is the ratio of the large segment (B) to the small segment (C). In other words, A is to B as B is to C.

This occurs only where: A is 1.618 times B and B is 1.618 times C.
	This ratio has been used by mankind for centuries. Its use started as early as with the Egyptians in the design of the Pyramids.
* diagrams and explanation provided by www.goldennumber.net, for more information on the golden ratio visit their site!
The SPIRAL® geotube is Designed using the Golden Ratio
The golden ratio is used today in the design of Spiral® geotubes.		H = Height of structure (given) A = Circumference B = Distance from one side of footprint to the other C = Width of Spiral® footprint H times 1.618 = C C times 1.618 = B B times 1.618 = A