An interesting fact can be noted down that is similar for absolute values and conjugates:

$$ |z| = a^2+b^2 $$

$$ z times z^* = a^2+b^2$$

This means that:

$$|z| =z times z^* $$.

Using simple algebra, we can rearrange these, and later be able to find an absolute value, given complex number and its conjugate, for example.