12. Rectangle Properties

using System;
using System.Numerics;

namespace Demo
{
    class Program
    {
        static void Main(string[] args)
        {
            double width = double.Parse(Console.ReadLine());
            double height = double.Parse(Console.ReadLine());

            double perimeter = 2 * (width + height);
            double area = width * height;
            double diagonal = Math.Sqrt(width * width + height * height);

            Console.WriteLine($"{perimeter}");
            Console.WriteLine($"{area}");
            Console.WriteLine($"{diagonal}");
        }
    }
}