13.Area of Figures

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

namespace _13.Area_of_Figures
{
    class Program
    {
        static void Main(string[] args)
        {
            string figure = Console.ReadLine();

            double areaoffigure = 0;

            if (figure.Equals("square"))
            {
                double side = double.Parse(Console.ReadLine());
                areaoffigure = side * side;
            }
            else if (figure.Equals("rectangle"))
            {
                double a = double.Parse(Console.ReadLine());
                double b = double.Parse(Console.ReadLine());
                areaoffigure = a * b;

            }
            else if (figure.Equals("circle"))
            {
                double radius = double.Parse(Console.ReadLine());
                areaoffigure = Math.PI * radius * radius;
            }
            else if (figure.Equals("triangle"))
            {
                double side = double.Parse(Console.ReadLine());
                double h = double.Parse(Console.ReadLine());
                areaoffigure = (side * h) / 2;
            }
            Console.WriteLine("{0}", Math.Round(areaoffigure, 3));
        }
    }
}