As shown in the diagram, NM is the median of trapezoid ABCD and PQ is the median of trapezoid ABMN. We know AB = 5 and DC = 19. Find PQ.
+591 The median of a trapezoid's length is the median of the two bases. So the median of ABCD is 12. Similarly, the median of ABMN's length is the median of the two bases AB and MN, so the length of PQ is $\boxed{8\frac12}$
