Deriving the Triangle Area Formula Practice Test

In triangle $UVW$, sides $UV$ and $UW$ are labeled $a$ and $b$, and the included angle $\angle VUW$ is labeled $C$. A dashed altitude from $W$ is drawn to side $UV$. Which expression represents the area of triangle $UVW$?

A non-right triangle $\triangle DEF$ is shown. Sides $DE=a$ and $DF=b$ form the included angle at $D$, labeled $C$. A dashed altitude from $E$ meets side $DF$ at a right angle. Which expression represents the area of the triangle?