Study guide and 3 practice problems on:

## Cross product length and the angle between vectors

If $\bfx$ and $\bfy$ are vectors and $\theta$ is the angle between them, then the length of their cross product is $$| \bfa \times \bfb | = | \bfa | | \bfb| \sin(\theta)$$
Two vectors have zero cross product if they are multiples of each other.