We have that the area of the brown tabletop is given by the following expression:

Let's find first the area of the green tabletop. If the base measures 7 feet and the height is 4 1/2 feet, then:

now that we know the area of the green tabletop, we can find the area of the brown tabletop:

therefore, the area of the brown tabletop is 47 1/4 ft^2