Find the Dot Product Of $\vec { u } = \langle 1,2,1 \rangle$

Multiple Choice

Find the dot product of $\vec { u } = \langle 1,2,1 \rangle$ and $\vec { v } = \langle 2,2,1 \rangle$ and the cosine of the angle between them.

A) $7 , \cos ( \theta ) = \frac { 7 } { 3 \sqrt { 6 } }$
B) $7 , \cos ( \theta ) = \frac { 7 } { 54 }$
C) $9 , \cos ( \theta ) = \frac { 1 } { 6 }$
D) $6 , \cos ( \theta ) = \frac { 1 } { 9 }$