Answer:
324 square feet (or whatever you call it i don't use feet and inches lol)
Explanation:
We gotta divide this into a trapezoid and a rectangle.
the rectangle part is easy which is 6x18=108
Then the trapezoid
b1=6 b2=18 h=18
6+18=24
24x18=432
432/2=216
now we add them 216+108=324