Perl Data Types: scalars

my $name   = 'Buffy';
my $age    = 12;

my $pi     = 3.14159;
my $radius = 6.378e3;

my $cgi    = new CGI;

print "Hello my name is $name and I am $age years old\n";

print "Earth's circumference: ", int($pi * $radius ** 2), "km\n";

print $cgi->header('text/plain');