# How do you find abs(-1 - 2i)?

Mar 29, 2016

$| - 1 - 2 i | = \sqrt{5}$

#### Explanation:

Let $z = x + i y$ be any complex number in rectangular form.

Then the modulus may be given by $| z | = \sqrt{{x}^{2} + {y}^{2}}$.

So in this particular case we get:

$| - 1 - 2 i | = \sqrt{{\left(- 1\right)}^{2} + {\left(- 2\right)}^{2}} = \sqrt{5}$.