Chapter 7 - Section 7.5 - Vectors: An Algebraic Approach - 7.5 Problem Set - Page 404: 29

$|V|=5.$

The magnitude of a vector is given by the possible square root of the sum of the squares of its horizontal and vertical components. Let $V=\langle -8,-3\rangle.$ Then \begin{align*} |V|&=\sqrt{(0)^{2}+(5)^{2}}\\ &=\sqrt{0+25}\\ &=\sqrt{25}\\ &=5. \end{align*} Hence, $|V|=5.$