AreaOfFigures - Chapter 3.0

//Task 013, Chapter 3.0
using System;

public class AreaOfFigures
{
    static void Main()
    {
        string figure = Console.ReadLine().ToLower();
        double area = 0;

        if(figure == "square")
        {
            double n = double.Parse(Console.ReadLine());
            area = n * n;
        }
        else if(figure == "rectangle")
        {
            double a = double.Parse(Console.ReadLine());
            double b = double.Parse(Console.ReadLine());
            area = a * b;
        }
        else if(figure == "circle")
        {
            double r = double.Parse(Console.ReadLine());
            area = Math.PI * r * r;
        }
        else if(figure == "triangle")
        {
            double a = double.Parse(Console.ReadLine());
            double h = double.Parse(Console.ReadLine());
            area = a * h / 2;
        }

        Console.WriteLine(Math.Round(area, 3));
    }
}