1997 AMC 12 Question 26

Triangle $ABC$ and point $P$ in the same plane are given. Point $P$ is equidistant from $A$ and $B,$ angle $APB$ is twice angle $ACB,$ and $\overline{AC}$ intersects $\overline{BP}$ at point $D.$ If $PB=3$ and $PD=2,$ then $AD\cdot CD=$