I have four questions:
1. The area of trapezoid ABCD is 60. One base is 4 units longer than the other, and the height of the trapezoid is 5. Find the length of the median of the trapezoid.
2. In trapezoid ABCD, line BC is parallel to line AD, angle ABD = 105 degrees, angle A = 43 degrees, and angle C = 141 degrees. Find angle CBD, in degrees.
3. The bases of trapezoid ABCD are lines AB and CD. Let M be the midpoint of line AD. If the areas of triangles ABM and CDM are 5 and 17 respectively, then find the area of trapezoid ABCD.
4. Let ABCD be a parallelogram. Extend line BC past B to F, and let E be the intersection of lines AB and DF. If the areas of triangles BEF and ADE are 1 and 9, respectively, find the area of parallelogram ABCD.