static void Main(string[] args)
{
Polygon polygon = new Pentagon(0, 0, 2, 0, 2, 2, 1, 3, 0, 2);
polygon.Show();
Console.Write(polygon.GetArea());
polygon = new Rectangle(0, 0, 4, 6);
polygon.Show();
Console.Write(polygon.GetArea());
polygon = new Square(0, 0, 4, 4);
polygon.Show();
Console.Write(polygon.GetArea());
}