Answer
$|5+12i|=13$
Work Step by Step
The plot of the given complex number, $ 5+12i ,$ is shown below.
The absolute value of the complex number $a+bi,$ written as $|a+bi|,$ is given by $\sqrt{a^2+b^2}.$ Therefore, the absolute value of the given complex number is \begin{align*} & \sqrt{(5)^2+(12)^2} \\&= \sqrt{25+144} \\&= \sqrt{169} \\&= 13 .\end{align*} Hence, $
|5+12i|=13
.$