## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$14$
Let us consider: $v=pi+qj+rz$ The magnitude of a vector can be determined using the formula $||v||=\sqrt{p^2+q^2+r^2} ...(1)$ We will use the formula (1) to obtain: $||v||=\sqrt{(-6)^2+(12)^2+(4)^2}\\ =\sqrt{36+144+16}\\ =\sqrt{196}\\ =14$