using System.Collections.Generic;
using System.Threading.Tasks;
namespace Shapes_and_stuff
public static void Main(string[] args)
Triangle triangle = new Triangle(10, 5);
Square square = new Square(70);
Rectangle rectangle = new Rectangle(3, 6);
Console.WriteLine("Triangle height = " + triangle.Height + ". Triangle baseline = " +
triangle.BaseLen + ". Triangle area = " + triangle.CalcArea() + ".");
Console.WriteLine("Square side = " + square.Side + ". Square area = " + square.CalcArea() + ".");
Console.WriteLine("Rectangle length = " + rectangle.Length + ". Rectangle width = " +
rectangle.Width + ". Rectangle area = " + rectangle.CalcArea() + ".");