# What is  || < 4 , -3 , -8 > || ?

Nov 15, 2016

$| | < 4 , - 3 , - 8 > | | = \sqrt{89} \approx 9.434$

#### Explanation:

In general we have:

$| | < a , b , c > | | = \sqrt{{a}^{2} + {b}^{2} + {c}^{2}}$

So in our example:

$| | < 4 , - 3 , - 8 > | | = \sqrt{{4}^{2} + {\left(- 3\right)}^{2} + {\left(- 8\right)}^{2}}$

$\textcolor{w h i t e}{| | < 4 , - 3 , - 8 > | |} = \sqrt{16 + 9 + 64}$

$\textcolor{w h i t e}{| | < 4 , - 3 , - 8 > | |} = \sqrt{89} \approx 9.434$