Program2.cs

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

namespace OOPGeometry2
{
    class Program
    {
        static void Main(string[] args)
        {
            Triangle triangle = new Triangle(10.0, 15.0);
            Rectangle rectangle = new Rectangle(5.0, 10.0);
            Circle circle = new Circle(12.0);

            Manager manager = new Manager(triangle);
            manager.TellTheSurface();

            manager.Figure = rectangle;
            manager.TellTheSurface();

            manager.Figure = circle;
            manager.TellTheSurface();

            Console.WriteLine("Hello");
            Console.Read();
        }
    }
}