15.Лица на фигури

using System;

class Area_Of_Figures
{
    static void Main()
    {
        string figures = Console.ReadLine();

        switch (figures)
        {
            case "square":
                double squareSide = double.Parse(Console.ReadLine());
                Console.WriteLine("{0}",Math.Pow(squareSide,2));
                break;
            case "rectangle":
                double rectangleSide1 = double.Parse(Console.ReadLine());
                double rectangleSide2 = double.Parse(Console.ReadLine());
                Console.WriteLine("{0}",rectangleSide1* rectangleSide2);
                break;
            case "circle":
                double radius = double.Parse(Console.ReadLine());
                Console.WriteLine("{0:F3}",Math.PI*Math.Pow(radius,2));
                break;
            case "triangle":
                double triangleSide = double.Parse(Console.ReadLine());
                double triangleheigth = double.Parse(Console.ReadLine());
                Console.WriteLine("{0}", (triangleSide* triangleheigth)/2);
                break;
            default:
                Console.WriteLine("incorrect input");
                break;
        }
    }
}