What is the magnitude of $\hat{i} - 4\hat{j} + 8\hat{k}$?

Explanation

1. 01

   $\lvert a\hat{i} + b\hat{j} + c\hat{k} \rvert = \sqrt{a^{2} + b^{2} + c^{2}}$.

2. 02

   $\sqrt{1 + 16 + 64} = 9$.