Explanation:
different to the suggested graphic representation, which goes wild with several complex sub-figures, I see simply a rectangle (2×9 × 4) at the bottom and a triangle standing on top of it (2×(9-6) × (16-4)).
the area of the rectangle is
2×9 × 4 = 18×4 = 72 ft²
the area of the triangle (remember : baseline × height / 2) is
2×(9-6) × (16-4) / 2 = 2×3 × 12 / 2 = 3×12 = 36 ft²
the total area is then
72 + 36 = 108 ft²