Answer:
lets use what we know.
given lengths are: 6, 3, 6, and 15.
We need to split the right triangle from the small little rectangle.
Now we add the lengths of the triangle to get the full length:
6 + 6 = 12
now we need to find the base:
15 - 3 = 12
Now we get our area of the triangle:
12 x 12 = 144
144 divided by 2 = 72
Now the small rectangle's area:
6 x 3 = 18
Add both of their areas to get:
72 + 18 = 90 ft2