Explanation:
the area is the sum of the top square of 9×9 and the bottom parallelogram.
we know the length of the parallelogram is still also the square side length : 9ft.
but we don't need to bother about the lengths of the inclined sides, as the area of a parallelogram is
baseline × height
and the height we can see on the right hand side, as the height of the total shape is 14ft. given that the square side length is 9ft, that leaves us with 14-9 = 5ft as the height of the parallelogram.
so, the area of the square is
9×9 = 81 ft²
the area of the parallelogram is
9×5 = 45 ft²
the total area is then
81 + 45 = 126 ft²