static void Main(string[] args)
{
Dot d1 = new Dot(0, 0);
Dot d2 = new Dot(0, 1);
Dot d3 = new Dot(1, 1);
Dot d4 = new Dot(1, 0);
Dot d5 = new Dot(0, 0);
Dot d6 = new Dot(0, 1);
Dot d7 = new Dot(0.5, 1);
Triangle tri = new Triangle(d5, d6, d7);
Quadrangle qua = new Quadrangle(d1, d2, d3, d4);
Console.WriteLine($"Triangle Area: {tri.countArea()}");
Console.WriteLine($"Quadrangle Area: {qua.countArea()}");
Console.WriteLine($"is Rectangle: {qua.isRectangle()}");
}
