The proportion of the division of a line so that the smaller part is to the larger part what the larger part is to the whole. This may be applied to the lengths of the sides of a rectangle. Classically this ratio has been used to define the size of objects as it is thought that this ratio yields objects that are pleasing to the eye. It is equal to the diagonal of a regular pentagon of unit side
- 1.618033988749894848204586834370 .......