# How do you find abs(7-9i)?

May 23, 2016

$| 7 - 9 i | = \sqrt{130}$

#### Explanation:

Absolute value of a complex number $a + i b$ is denoted as $| a + i b |$

and is given by $\sqrt{{a}^{2} + {b}^{2}}$

Hence absolute value $| 7 - 9 i |$ is

$\sqrt{{7}^{2} + {9}^{2}} = \sqrt{49 + 81} = \sqrt{130}$