($latitude,$longitude)=ll(
                        MILES=>5,
                        LATITUDE=>51+29/60,
                        LONGITUDE=>0+0/60,
                        DIRECTION=>315,
                         );

if( $latitude < 0 ){
  $latitude *= -1;
  $ns='S';
}else{
  $ns='N';
}
if( $longitude < 0 ){
  $longitude *= -1;
  $ew='W';
}else{
  $ew='E';
}  
print int $latitude,"°",60*($latitude-int $latitude),"' $ns\n",
      int $longitude,"°",60*($longitude-int $longitude),"' $ew\n";
use Math::Trig;
sub ll{
    my %l=@_;
    use constant PI=>4*atan2(1,1);
    my $nm = $l{MILES}*.87;
    my $A=$l{DIRECTION}*PI/180;
    my $b=(90-$l{LATITUDE})*PI/180;
    my $c=$nm/60/180*PI;
    my $a=acos(cos($b)*cos($c)+sin($b)*sin($c)*cos($A));
    my $latitude=90-180/PI*$a;
    my $C=asin(sin($c)*sin($A)/sin($a));
    my $longitude=$l{LONGITUDE}+180/PI*$C;
    return $latitude,$longitude;
}
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