C :

#include<stdio.h>
int main(){
int a;
  while(scanf("%d",&a)!=EOF)
  {
    printf("%.2lf\n%.2lf",2*a*3.1415,a*a*3.1415);
  }
}

C++ :

#include<iostream>
#include<cstdio>
using namespace std;
int main()
{
	float r,s1,s2;
	cin>>r;
	s1=3.1415*2*r;
	s2=3.1415*r*r;
	printf("%.2f\n",s1);
	printf("%.2f\n",s2);
	return 0;
}

Pascal :

program p5683;
  const pi=3.1415;
  var r,l,s:real;
begin
  read(r);
  l:=2*pi*r;
  s:=pi*r*r;
  writeln(l:4:2);
  writeln(s:4:2);
end.