c# question ?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Square_Point_Line
{
    public class Point
    {
        public Point()
        {

        }

        public Point(double x,double y)
        {
            this.X = x;

            this.Y = y;
        }
        public double X { get; set; }

        public double Y { get; set; }


        /// <summary>
        /// This Function Shows the Coordinates of the Point
        /// </summary>
        public void ShowPoint()
        {
            Console.WriteLine("\t\n [x={0},y={1}]",X,Y);
        }
    }


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Square_Point_Line
{
 
    public class Line
    {

        public Line()
        {

        }

        public Line(Point a,Point b)
        {
            this.A = a;

            this.B = b;

        }

        public double Length
        {
            get
            {
                 return Math.Sqrt(Math.Pow(A.X - B.X, 2) + Math.Pow(A.Y - B.Y, 2));
            }
        }

        public Point A { get; set; }

        public Point B { get; set; }


        /// <summary>
        /// This Function Shows the Length of Line
        /// </summary>
        public void DisplayLine()
        {
            Console.WriteLine("LengthOfLine={0}",this.Length);
        }
    }
}



using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace Square_Point_Line
{
    public class Square
    {
        public Square()
        {

        }
        public Square(Line ab,Line bc,Line cd,Line da)
        {
            this.AB = this.BC = this.CD = this.DA = ab;
        }

        public Square(Point a,Point b,Point c,Point d)
        {
            this.A = a;
            this.B = b;
            this.C = c;
            this.D = d;
        }
        public Line AB { get; set; }
        public Line BC { get; set; }
        public Line CD { get; set; }
        public Line DA { get; set; }

        public Point A { get; set; }
        public Point B { get; set; }
        public Point C { get; set; }
        public Point D { get; set; } 
   
    }
}

}