Answer
$180^{o}$
Work Step by Step
The angle of $\vec{v}=\vec{b}-\vec{a}$
relative to the +x axis is $80^{o}$, as found in part (f).
The angle of $\vec{w}=\vec{a}-\vec{b}$
relative to the +x axis is $260^{o}$, as found in part (j).
Thus, the abgle between $\vec{v}$ and $\vec{w}$ is $260^{o}-80^{o}=180^{o}.$
This means that the two vectors are antiparallel (they point in opposite directions).
