70 in^2
Lets split the trapezoid into a rectangle and a right triangle. To find the area of the rectangle we multiply 8 in by 7 in to get 56 in^2. Next we find the area of the triangle. The base of the triangle is 4 in since the bottom of the trapezoid was originally 12 in and had 8 in removed to the rectangle. To find the area of the triangle we multiply the base of 4 in by the height of 7 in by 1/2 to get 14 in^2. Finally, to find the total area of the trapezoid we simply add together the area of the rectangle (56 in^2) with the area of the triangle (14 in^2) to get a total of 70 in^2.
We can also use the formula ((a+b)/2)h
((a+b)/2)h
((8 in + 12 in) / 2)(7 in)
(20 in / 2)(7 in)
(10 in)(7 in)
70 in^2