Answer:
89 m²
Step-by-step explanation:
It should be no surprise that the area can be found as the difference between the area of the enclosing rectangle and the area of the triangular cutout.
The rectangle area is given by ...
A = LW
A = (13 m)(8 m) = 104 m²
The base width of the triangular cutout is 13 m - 4 m - 4 m = 5 m. The area of that cutout is given by ...
A = 1/2bh
A = 1/2(5 m)(6 m) = 15 m²
Then the area of the shaded figure is ...
104 m² -15 m² = 89 m²
