Suppose a circle is divided by two radii and the two arcs *a* and *b* are in the golden ratio:

*b* / *a* = ( *a + b *) / *b* = *φ* ≈ 1.618

Then the smaller angle formed by the radii is called the golden angle. It is equal to about 137.5° or 2.4 radians. We will denote the golden angle by *γ*. Its exact value, as a fraction of a complete circle, is ( 3 – √5 ) / 2 ≈ 0.382 cycles.