 It measures approximately 137.5077640500378546463487 ...° or in radians 2.39996322972865332 ... .The name comes from the golden angle's connection to the golden ratio "φ"; the exact value of the golden angle is

or

where the equivalences follow from well-known algebraic properties of the golden ratio.The golden ratio is equal to "φ" = "a"/"b" given the conditions above.