In trapezoid ABCD, the parallel sides AB and CD have lengths of 8 and 20 units, respectively, and the altitude is 12 units. Points E and F are the midpoints of sides AD and BC, respectively. What is the area of quadrilateral EFCD in square units?
The length of side EF is the average of the lengths of the bases AB and CD of trapezoid ABCD. EF = (8 + 20)/2 = 14 Trapezoid EF has bases 14 and 20. The height of trapezoid EFCD is half the height of trapezoid ABCD, or 6.
A = (B + b)h/2 = (20 + 14) * 6 / 2 = 102
Answer: The area of trapezoid EFCD is 102 square units
