9 1/4 = 9.25
8 4/5 = 8.8
The area of a rectangle ( the shape of the base ) is:
A = lw, where A = area, l = length and w = width.
So:
A = (9.25)×(8.8)
A = 81.4
So, the total are of the model house's base is 81.4 square feet, or 81 and 2/5 square feet.