To solve you must find the area of the triangle plus the area of the rectangle:
Area of Triangle = 1/2 base * height
Area of Rectangle = length * width
The area of the rectangle is:
16 * 8 = 128
The area of the Triangle:
Find the base first, since we know that two sides of a rectangle are equal, the top missing portion must equal 16
12 + triangle base = 16
Triangle base = 4
Height = 6
Area = 3 * 4 = 12
Now add:
128 + 12 = 140feet(squared)
Always bring your units