equal to 1. In SI 2019, the SI radian is defined accordingly as 1=1 rad = 1. It is a long-established practice in mathematics and across all areas of science to make use of .

Giacomo Prando writes "the current state of affairs leads inevitably to ghostly appearances and disappearances of the radian in the dimensional analysis of physical equations". For example, an object hanging by a string from a pulley will rise or drop by centimetres, where is the magnitude of the radius of the pulley in centimetres and