[ Symmetry and Constructions ]

Construct triangle $ABC$, given points $A, B$ and the line on which the bisector of angle $C$ lies.
Let point $A^{\prime}$ be symmetric to point $A$ with respect to the bisector of angle $C$. Then $C$ is the point of intersection of the line $A^{\prime} B$ and the line on which the bisector of angle $C$ lies.