The area of a trapezoid is given as
[tex]A=\frac{1}{2}(a+b)h[/tex]From the given trapezoid
[tex]a=13ft,b=31ft,h=16ft[/tex]Substitute the values of a, b, and h into the equation
This gives
[tex]A=\frac{1}{2}(13+31)\times16[/tex]Calculate the value of A
[tex]\begin{gathered} A=\frac{1}{2}(44)\times16 \\ A=44\times8 \\ A=352 \end{gathered}[/tex]Therefore the area of the trapezoid is
[tex]352ft^2[/tex]