1.
EF is the median of the trapezoid ABCD, thus

units.
2.
The median EF bisects the altitude into 2 segments of equal length 6 units.
Thus the height of trapezoid EFCD is 6, and its 2 bases have length 14 and 8 units.
3.
From the area of the trapezoid formula:

(square units)
Answer: 66 square units