#### Answer

The median is parallel to each base and has a value equal to the average of the bases.

#### Work Step by Step

We first assign coordinates:
$A: 0,0;\\ B: 2b,2c;\\ C: 2d,2c;\\ D: 0,2a$
We find the slope of the segment attaching the midpoints:
$m = \frac{c-c}{d-b-a}=0$
Thus, it is parallel to the x-axis, which is parallel to each base.
Its length is: $=b+a-d$. The average length of the two bases is: $=\frac{2b-2d+2a}{2} =b+a-d$. Thus, the median is parallel to each base and has a value equal to the average of the bases.