Deriving the Triangle Area Formula Practice Test

In right triangle $$ABC$$ with right angle at $$C$$, $$\sin A = \frac{5}{13}$$ and the area of the triangle is 30 square units. What is the perimeter of triangle $$ABC$$?

Triangle $\triangle WXY$ is shown in the plane (not necessarily right). Side $\overline{WX}$ is labeled $a$ and side $\overline{WY}$ is labeled $b$. The included angle at $W$ is labeled $C$ (so $C=\angle XWY$). A dashed altitude from $Y$ meets $\overline{WX}$ at $Z$, with $\overline{YZ}\perp\overline{WX}$. Which expression represents the area of $\triangle WXY$?