Answer
$\frac{63}{4}\ unit^2$
Work Step by Step
Use the given figure, assume side $9$ as the base, the height can be found as $h=7sin(180-150)^\circ=\frac{7}{2}$. Thus the area of the triangle is $A=\frac{1}{2}(9)(\frac{7}{2})=\frac{63}{4}\ unit^2$
