#!/usr/bin/perl -w
use Math::Trig; #allows to use the Math::Trig module that is part of perl
$circumference=0; #reset variables
$radius=0;
print " Input the Radius \n ";
$radius=<STDIN>;
chomp($radius);
$circumference= 2*$radius*pi;
print "\nwith radius=$radius ,\nthe circumference is $circumference\n\n";