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()}"); }