Golden angle

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

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.

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:

$\frac{a+b}{a}=\frac{a}{b}$

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