If the adjacent sides of a rectangle are $\bar{a}=5 \bar{m}-3 \bar{n}, \bar{b}=-\bar{m}-2 \bar{n}$ and the…
If the adjacent sides of a rectangle are $\bar{a}=5 \bar{m}-3 \bar{n}, \bar{b}=-\bar{m}-2 \bar{n}$ and the adjacent sides of another rectangle are $\bar{c}=-4 \bar{m}-\bar{n}, \bar{d}=-\bar{m}+\bar{n}$, then the angle between the vectors $\bar{x}=\frac{\bar{a}+\bar{c}+\bar{d}}{3}$ and $\bar{y}=\frac{\bar{c}+\bar{d}}{5}$ is