Working with List && OOP

class Program
{
  abstract class Shape
    {
        public string Name { get; set; }
        public string Color { get; set; }
        public abstract double GetPerimeter();
        public Shape(string name,string color)
        {
            this.Name = name;
            this.Color = color;
        }

    }
     class MyCircle : Shape
    {
        public double Radius { get; set; }
        public MyCircle(string name,string color,double radius)
            :base(name,color)
        {
            this.Radius = radius;
        }
        public override double GetPerimeter()
        {
            return Math.PI * Radius * 2;
        }
    }

    class MyRectangle : Shape
    {
        public double A { get; set; }
        public double B { get; set; }
        public MyRectangle(string name,string color,double a,double b)
            :base(name,color)
        {
            this.A = a;
            this.B = b;
        }
        public override double GetPerimeter()
        {
            return (A + B) * 2;
        }
    }
        public double A { get; set; }
        public double B { get; set; }
        public double C { get; set; }
        public MyTriangle(string name,string color,double a,double b,double c)
            :base(name,color)
        {
            this.A = a;
            this.B = b;
            this.C = c;
        }
        public override double GetPerimeter()
        {
            return A + B + C;
        }
            static void Main(string[] args)
           {
                MyCircle circle = new MyCircle("circle1","green",2);
                MyRectangle rectangle = new MyRectangle("rectangle1","black",4,2);
                MyTriangle triangle = new MyTriangle("triangle1","red",2,4,9);
                List<Shape> shapes = new List<Shape>();
                shapes.Add(circle);
                shapes.Add(rectangle);
                shapes.Add(triangle);
                 foreach (Shape item in shapes)
                {
                    Console.WriteLine(item.Name+", "+item.Color+", "+item.GetPerimeter());
                }
}