When the trapezoid is an isosceles trapezoid, CE=4.
Because AEB = CDE+C, ABC = Abd+DBC.
Because the quadrilateral is an isosceles trapezoid, BD=DC.
So ∠AEB=∠ABC, ∠ DBC = ∠ C.
So ∠CDE=∠ABD
It can be proved that △ABD is congruent △DEC(SAS).
CE=AD=4。
When the trapezoid is a right-angled trapezoid, CE=6.
Don't erase that isosceles trapezoid, it helps to do the problem! At this time, e is recorded as m, and e in isosceles trapezoid is still e).
Do DM⊥BC
Because the quadrangle ABDE is an isosceles trapezoid
So ME=2 (you can get it by making two vertical lines along a and d)
Because CE=4 and CM=6, it is actually CE=6.
direct proofs
If you want a map, just tell me. I can upload it.