What common angle do ace and acd share?

∠ACE≅∠ECA

Step-by-step explanation:

If we take ΔACE and ΔACD,

∠ACE and ∠ECA are the common angle as compared to the rest one given.

If we take, ∠AFB and ∠EFD, both the angles are not contained in the given triangle.

Similarly, if we take ∠EBC and∠ECB, the ∠EBC is not included in the triangle ACE.

In, ∠CAD and ∠CEB, both the angles cannot be equal.