/// <summary>
/// Odległość punktów
/// </summary>
/// <param name="x1"></param>
/// <param name="y1"></param>
/// <param name="x2"></param>
/// <param name="y2"></param>
/// <returns></returns>
public static double PointDistance(double x1, double y1, double x2, double y2)
{
return((double)Math.Sqrt(Wektor.PointDistance2(x1, y1, x2, y2)));
}