Answer:
6.75
Explanation:
Find the relationship between the trapezoids. You can see that the top of trapezoid ABFE is 3 units and the top of EFCD is 4.5 units. 3 * 1.5 = 4.5, so t the sides of trapezoid EFCD are 1.5 times more than the sides of ABFE.
Now, you know the bottom of ABFE is 4.5, so the bottom of EFCD is 1.5 times longer because they are proportional, so you can do 4.5 * 1.5 = 6.75 units.