The area of a rectangle is found by multiplying the length by the width.
To find the area of the base of Isabella's fort, we will use the following formula:
Area = length x width
We are given that the base of the fort is 78 inches wide and 92 inches long. So we can plug these values into the formula:
Area = 78 inches x 92 inches = 7176 square inches
Therefore, the area of the base of Isabella's fort is 7176 square inches.