TITLE: Finding magnitude of a complex number
QUESTION [7 upvotes]: $$z = \dfrac{2+2i}{4-2i}$$
$$|z| = ? $$

My attempt:
$$\dfrac{(2+2i)(4+2i)}{(4-2i)(4+2i)} = \dfrac{4+12i}{20} = \dfrac{4}{20}+\dfrac{12}{20}i = \dfrac{1}{5} + \dfrac{3}{5}i$$
Now taking its magnitude and we have that
$$|z| = \sqrt{\biggr (\dfrac 1 5 \biggr ) ^2 +\biggr (\dfrac 3 5 \biggr )^2} = \sqrt {\dfrac 2 5 }$$
Am I right?

REPLY [3 votes]: It is better to use $$\left|\dfrac ab\right|=\dfrac{|a|}{|b|}$$
$|2+2i|=\sqrt{2^2+2^2}=2\sqrt2$