Geometry: Measure of angles

Question

The area of a triangle is equal to 48 cm^2 and two if its sides measure 12 cm and 9 cm, respectively. Find the possible measures of the included angles of the given sides.

Answer 1

Hint: Use the formula $Area=\frac{1}{2}ab sinC$ where $a$ and $b$ are measures of two sides of a triangle and $C$ is the included angle. Just substitute $148cm^{2}$ for the area and $12cm$ and $9cm$ for $a$ and $b$.