2.10.1. Problem

2.10.2. Solution

Convert between radians and degrees (2π radians equals 360 degrees):

use constant PI => (4 * atan2 (1, 1));

sub deg2rad {
    my $degrees = shift;
    return ($degrees / 180) * PI;
}

sub rad2deg {
    my $radians = shift;
    return ($radians / PI) * 180;
}

use Math::Trig;

$radians = deg2rad($degrees);
$degrees = rad2deg($radians);

2.10.3. Discussion

If you're looking for the sine in degrees, use this:

# deg2rad and rad2deg defined either as above or from Math::Trig
sub degree_sine {
    my $degrees = shift;
    my $radians = deg2rad($degrees);
    my $result = sin($radians);

    return $result;
}