Problem:
Circle

Write a program which calculates the area and circumference of a circle for given radius r.

Input

A real number r is given.

Output

Print the area and circumference of the circle in a line. Put a single space between them. The output should not contain an absolute error greater than 10-5.

Constraints

0 < r < 10000

Sample Input 1

2

Sample Output 1

12.566371 12.566371

Sample Input 2

3

Sample Output 2

28.274334 18.849556

Solution in C# (judge verdict: Accepted)

using System;
using System.Linq;
using System.Collections.Generic;
public class Hello{
    public static void Main(){
        var r = double.Parse(Console.ReadLine());
        
        var c = Math.Round(r * 2 * Math.PI,6,MidpointRounding.AwayFromZero);
        var s = Math.Round(Math.Pow(r,2) * Math.PI,6,MidpointRounding.AwayFromZero);
        Console.WriteLine($"{s} {c}");
    }
}