GetAngle

function GetAngle(

  const origin: TPoint;

  const pt: TPoint

):Double; overload;

function GetAngle(

  const origin: TPointD;

  const pt: TPointD

):Double; overload;

function GetAngle(

  const a: TPoint;

  const b: TPoint;

  const c: TPoint

):Double; overload;

function GetAngle(

  const a: TPointD;

  const b: TPointD;

  const c: TPointD

):Double; overload;