The angle bisector of angleBACis a rayADsuch thatADis betweenABandACand the measure of angleBAD= the measure of angleDAC. The distance from a point to a line is measured along a perpendicular.

Prove the following theorem.Pointwise Characterization of Angle Bisector.A pointPlies on the bisector of angleBACif and only ifPis in the interior of angleBACand the distance fromPtoABequals the distance fromPtoAC.