Area of Figures

using System;

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

            if (figure == "square")
            {
                double square = double.Parse(Console.ReadLine());
                double sqAnswer = square * square;
                Console.WriteLine($"{sqAnswer:F3}");
            }


            if (figure == "rectangel")
            {
                double rectangel = double.Parse(Console.ReadLine());
                double rectangel2 = double.Parse(Console.ReadLine());
                double recAnswer = rectangel * rectangel2;
                Console.WriteLine($"{recAnswer:F3}");
            }

            if (figure == "circle")
            {
                double circle = double.Parse(Console.ReadLine());
                double cirAnswer = Math.PI * circle * circle;
                Console.WriteLine($"{cirAnswer:F3}");
            }

             if (figure == "triangle")
            {
                double triangle = double.Parse(Console.ReadLine());
                double triangle2 = double.Parse(Console.ReadLine());
                double triAnswer = 0.5 * triangle * triangle2;
                Console.WriteLine($"{triAnswer:F3}");
            }
        }
    }
}