#### Answer

If two sides $a$ and $b$ and the included angle $C$ are known in a triangle, then the area of the triangle is found using the formula $\text{Area}=\underline{\frac{1}{2}ab\sin C}$.

#### Work Step by Step

$\text{Area}=\frac{1}{2}a\times h$ ……1
Also,
$h=b\times \left( \sin C \right)$ ……2
Substituting equation 2 with equation 1, we get
$Area=\frac{1}{2}ab\times \left( \sin C \right)$
Hence, we can use this to find the area of the triangle.