Sortable Shapes

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

namespace CodeKata
{

    public abstract class Shape
    {
        public double Side { get; set; }
        public double Radius { get; set; }
        public double Base { get; set; }
        public double Height { get; set; }
        public double Width { get; set; }


        public abstract double Size ();
    }
        public class Square : Shape
        {
            public override double Size() => Side * Side;
            public Square(double side)
            {
                Side = side;
                Size();
            }
        }
        public class Rectangle : Shape
        {
            public override double Size() => Width * Height;
            public Rectangle(double width, double height)
            {
                Width = width;
                Height = height;
                Size();
            }
        }
        public class Triangle : Shape
        {
            public override double Size() => (Base * Height) / 2;
            public Triangle(double triangleBase, double height)
            {
                Base = triangleBase;
                Height = height;
                Size();
            }
        }
        public class Circle : Shape
        {
            public override double Size()
            {
                const double pi = System.Math.PI;
                return Radius * pi;
            }
            public Circle(double radius)
            {
                Radius = radius;
                Size();
            }
        }
        public class CustomShape : Shape
        {
            public override double Size()
            {
                return Side;
            }
            public CustomShape(double side)
            {
                Side = side;
                Size();
            }
        }
}