$ cat math1.pm
package math1;
require Exporter;

our @ISA = qw(Exporter);
our @EXPORT = qw( pi degrees_to_radians);

sub pi{
use 5.010;
use Math::Trig ':pi';

my $a = pi;
return $a;
}

sub degrees_to_radians{
use 5.010;
use Math::Trig qw(deg2rad);

my $a = shift;
my $b = deg2rad($a);
return $b;
}

1;

$