In order to find the area of the trapezoid, consider the figure as formed by two right triangles with the same area, and one rectangle.
Then, if A1 is the area of one triangle and A2 is the area of the rectangle, you have for the area of the trapezoid:
A = 2A1 + A2
where, for the triangle you have:
A1 = b·h/2
b = (16 ft - 6ft)/2 = 5 ft
h = 12 ft
A1 = (5 ft)(12 ft)/2 = 30 ft²
and for the rectangle:
A2 = w·h
w = 6 ft
h = 12 ft
A2 = (6 ft)(12 ft) = 72 ft²
next, replace the values of A1 and A2 to get the area of the trapezoid:
A = 2(30 ft²) + 72 ft²
A = 60 ft² + 72 ft²
A = 132 ft²
Hence, the area of the given trapezoid is 132 ft²
the following is a figure of the trapezoid as formed by two triangle and one rectangle: