Golden angle

division of 360° angle into two sub-angles, such that one is 1.618034 times bigger than the other (i.e. the golden ratio or ɸ)

In Geometry, the golden angle is the smaller of the two angles created by sectioning the circumference of a circle according to the golden ratio into two arcs.

The golden angle is the angle subtended by the smaller (red) arc when two arcs that make up a circle are in the golden ratio

according to algebra, let a+b be the circumference of a circle, divided into a longer arc of length a and a smaller arc of length b such that:

The golden angle is then the angle subtended by the smaller arc of length b.