Use the Dot Product to Find the Magnitude of U $\mathbf { u } = \langle 6 , - 2 \rangle$

Multiple Choice

Use the dot product to find the magnitude of u if $\mathbf { u } = \langle 6 , - 2 \rangle$

A) $\| \mathbf { u } \| = 4$
B) $\| \mathbf { u } \| = 12$
C) $\| \mathbf { u } \| = 20$
D) $\| \mathbf { u } \| =$ $4 \sqrt { 10 }$
E) ​ $\| \mathbf { u } \| =$ $2 \sqrt { 10 }$