Hi Guest!
There's many ways to approach this problem. You could graph it and then split it into other shapes, or you could use the shoelace theorem. I'm sure there's other ways to solve this, but these are the only ways I know.
1. Shoelace
If you're not familiar with the Shoelace Theorem, there's many good youtube videos out there that explain it well.
Anyways, you should get:
\(\frac{1}{2}[0+0+24+30-(0+0+0+12)]=\boxed{21}.\)
So, the area of the quadrilateral is 21.
I hope this helped you, guest!
:)