Let the parallelogram be $ABCD$ with sides $AB = 12$ cm and $BC = 14$ cm.
Let the diagonals be $AC$ and $BD$, where $AC = 16$ cm.
The formula for the length of the diagonals in a parallelogram is given by:
$ d_1^2 + d_2^2 = 2(a^2 + b^2) $
where
$a = 12$ cm, $b = 14$ cm, $d_1 = 16$ cm, and $d_2$ is the unknown diagonal.
Substituting the values:
$ 16^2 + d_2^2 = 2(12^2 + 14^2) $
$ 256 + d_2^2 = 2(144 + 196) $
$ 256 + d_2^2 = 2(340) $
$ 256 + d_2^2 = 680 $
$ d_2^2 = 680 - 256 $
$ d_2^2 = 424 $
$ d_2 = \sqrt{424} $
$ d_2 \approx 20.6 $ cm
Thus, the length of the other diagonal is:
$\boxed{20.6}$ cm