B and E are both 44.5 degrees.
Set (2.5x+8) equal to (3.5x-7) since they are congruent
Evaluate to find that x=15
Plug 15 in for x: 2.5(15)+8 = 45.5
Remember all angles must add up to 180 degrees
45.5 (F or C) + 90 (A or D) = 135.5
180 - 135.5 = 44.5
44.5 is your answer!
hope this helps :)
