Answer: 61 unit^2
Step-by-step explanation:
ABCD is a rectangle with dimensions 12 by 11, for a total area of 132 (square units). Although I could determine the lengths of the parallel lines of the interior trapezoid from the data supplied, I'm lazy and decided, instead, to subtract from the total rectangle area the areas of the four right triangles formed outside the shaded area. The area of each triangle is (1/2)b*h, and we are given those dimensions on the figure.
The four triangle areas:
TriD = 36
TriA = 6
TriB = 20
TriC = 9
Total area = 71 square units.
Subtract this from the rectangle's area: 132 - 71 = 61 units^2
This is the area of the shaded trapezoid.
