Area of triangle when two sides and angle given but not in between the two sides

Question

What should be the formula to replace area of triangle.

Answer 1

Hint to get you started:

• First use the formula for the area of triangle

$$\frac12 ab \sin \theta$$ to determine one of the unknown side.

• After that use a different formula to determine $x$.

Answer 2

As per @Siong comment, this is my answer.