Answer
$A=79.2~in^{2}$
Work Step by Step
The formula to calculate the area of the triangular gusset is
$A=\frac{bh}{2}$
where the sides are:
$b=14.4 in$
$h = 11 in$
Thus, we have:
$A=\frac{bh}{2}=\frac{(14.4in)(11.0in)}{2}=79.2~in^{2}$