use feature ":5.14";
use warnings FATAL => qw(all);
use strict;
use Data::Dump qw(dump pp);

my $wheel = 2100; 
my @chwhs = qw (23 26  27);                  # test data
my @cogs  = qw (11 13 15 17 19 21 24 28 32); # test data

my $gear;

for my $c(0..2)
 {$gear->[$c][$_] = $wheel*$chwhs[$c]/$cogs[$_] for 0..8;
 }

pp($gear);