Answer
$9$
Work Step by Step
Area $=\displaystyle \frac{1}{2}$ (base)$\times$(height).
We take the side $AB$ as base since it is parallel to the x-axis.
The height is the change in the y-coordinates to the point C, opposite the base
base = $|-2-4|=6$
height is $|4-1|=3$.
Area = $\displaystyle \frac{1}{2}(6\cdot 3)=9$.
