Answer
$-2,100.3^\circ$
Work Step by Step
1. Use the given vectors, we have:
$\vec v\cdot\vec w=(2)(1)+(1)(2)+(-3)(2)=-2$
2. Thus angle between the vectors:
$\theta=cos^{-1}(\frac{\vec v\cdot\vec w}{||\vec v||||\vec w||})=cos^{-1}(\frac{-2}{\sqrt {4+1+9}\sqrt {1+4+4}})\approx100.3^\circ$
