7. Area of Figures

using System;

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

        if (figureType == "square")
        {
            double side = double.Parse(Console.ReadLine());
            double result = side * side;
            Console.WriteLine($"{result:F3}");
        }
        else if (figureType == "rectangle")
        {
            double length = double.Parse(Console.ReadLine());
            double width = double.Parse(Console.ReadLine());

            double result = length * width;
            Console.WriteLine($"{result:F3}");
        }
        else if (figureType == "circle")
        {
            double radius = double.Parse(Console.ReadLine());

            double result = radius * radius * Math.PI;
            Console.WriteLine($"{result:F3}");
        }
        else if (figureType == "triangle")
        {
            double bottom = double.Parse(Console.ReadLine());
            double height = double.Parse(Console.ReadLine());

            double result = (bottom * height) / 2;
            Console.WriteLine($"{result:F3}");
        }
    }
}
}