Answer:
1344 ft^2
Explanation:
From the picture we can see that 4w = 3l, which means that l = (4/3)w. Since w = 12 ft, l = (4/3)(12 ft) = 16 ft. Then the total area of the floor is
(length of floor)(width of floor) = (48 ft)(12 ft + 16 ft) = 1344 ft^2