# How do you find abs(3+4i)?

The modulus $| a + b i |$ is $\sqrt{{a}^{2} + {b}^{2}}$
In this case $a = 3 , b = 4$, so the modulus $| 3 + 4 i |$ is:
$\sqrt{{3}^{2} + {4}^{2}} = \sqrt{9 + 16} = \sqrt{25} = 5$