39. In trapezoid $A B C D$ with sides $|A B|=a$, $|B C|=b$, the bisector of angle $A$ is drawn. Determine whether it intersects: base $B C$ or lateral side $C D$.
39. If $a>b$, then the bisector intersects the lateral side $C D$; if $a<b$, then the base $B C$.