use 5.010;
use strict;
use warnings;

$_ = `cat data.txt`;
s/\b[a-z]/\$::$&/g;
eval;

no warnings 'once';
say $::x1 * $::y1;
say $::x2 * $::y2;
say $::x3 * $::y3;
say +($::x1 * $::y1) / $::x2;

__END__
38.38
67.28
52.07
6.61724137931034483