Answer:
121 ft^2
Explanation:
I'm going to tell you my method, which differs through teachers (I'm a student lol).
I find the total area and then subtract the white space.
13 * 11 = 143 gives you the area including the white space.
You can subtract the 9 from 13 to find the width of the white space, and we know the length is 11 since is the same on the other side.
13 - 9 = 4
4 * 11 = 44
This is a triangle, so you divide the rectangle calculated by 2.
44/2 = 22.
The area stated earlier was 143, and you subtract the 22.
143 - 22 = 121