In circular measure, the value of the angle 12° 30' is:

         12°30' = 12° + \(\frac{30°}{60}\)

                   = 12 + \(\frac{1}{2}\) = \(\frac{25°}{2}\)                          ( 180° = π )

                   = \(\frac{π}{180}\) × \(\frac{25}{2}\) = \(\frac{5π}{72}\)