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 JAVA (judge verdict: Accepted)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {

	public static void main(String[] args) throws IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        double r=Double.parseDouble(br.readLine());

        double x=Math.PI;

        double a=r*r*x;
        double b=2*x*r;

        double c = a;
        String menseki=String.format("%.6f",c);
        c = b;
        String gaisyu=String.format("%.6f",c);

        System.out.println(menseki+" "+gaisyu);
	}

}