We have that the area of the brown tabletop is given by the following expression:
[tex]A_b=1\frac{1}{2}\cdot A_g[/tex]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:
[tex]\begin{gathered} A_g=b\cdot h_{} \\ \Rightarrow A_g=(7)\cdot(4\frac{1}{2})=7\cdot(\frac{9}{2})=\frac{63}{2}=31\frac{1}{2} \\ A_g=31\frac{1}{2}ft^2 \end{gathered}[/tex]now that we know the area of the green tabletop, we can find the area of the brown tabletop:
[tex]\begin{gathered} A_b=1\frac{1}{2}\cdot A_g \\ A_g=31\frac{1}{2} \\ \Rightarrow A_b=1\frac{1}{2}\cdot(31\frac{1}{2})=(\frac{3}{2})(\frac{63}{2})=\frac{189}{4}=47\frac{1}{4} \\ A_b=47\frac{1}{4}ft^2 \end{gathered}[/tex]therefore, the area of the brown tabletop is 47 1/4 ft^2