The angle between vectors $(\overrightarrow {\rm{A}} \times \overrightarrow {\rm{B}} )$ and $(\overrightarrow {\rm{B}} \times \overrightarrow {\rm{A}} )$ is
Zero
$\pi$
$\pi /4$
$\pi /2$
The angle between vectors $(\overrightarrow {\rm{A}} \times \overrightarrow {\rm{B}} )$ and $(\overrightarrow {\rm{B}} \times \overrightarrow {\rm{A}} )$ is
$\vec A \times \vec B$ and $\vec B \times \vec A$ are parallel and opposite to each other. So the angle will be $\pi$.