using System;

public class Program

{

        public static (double Area, double Perimeter) circleAreaPerimeter(double r)

        {

            double perimeter, area;          

            perimeter = 2 * 3.14 * r;

            area = 3.14 * Math.Pow(r, 2);

            return (area, perimeter);

        }

       static void Main(string[] args)

       {

            Console.Write("Please write the radius of your circle : ");

            double  r = Convert.ToDouble(Console.ReadLine());

            var result = circleAreaPerimeter(r);

            Console.WriteLine("The perimeter of yor circle : {0}", result.Perimeter);

            Console.WriteLine("The area of yor circle : {0}", result.Perimeter);

            Console.ReadLine();

       }        

    }

​