Pi                       Predefined Real Constant (3.1415926536)

 Pi

    A real constant containing a value equal to the ratio between the
    circumference and the diameter of a circle (Pi =
    circumference/diameter). This number is useful for converting degrees
    to radians for use with the Sin, Cos, and ArcTan functions. The
    formula for this conversion is:

         radians := degrees * 2 * Pi / 180.

  -------------------------------- Example ---------------------------------

           X := ArcTan(1) * (180/Pi);       { X = 45 (degrees) }