C# - Berechnung Kugelvolumen/Kugeldurchmesser

private static double Pi = Math.PI;

        public static double diameter(double diameter)
        {
            double vol = Math.Pow(diameter, 3) * Pi / 6.0;
            return vol;
        }

        public static double volume(double volume)
        {
            double dia = Math.Pow(6 / Pi * volume, 1 / 3.0);
            return dia;
        }