Read the proof.
given: aeec; bddc
prove: △aec ~ △bdc

statement reason
1. aeec; bddc 1. given
2. ∠aec is a rt. ∠; ∠bdc is a rt. ∠ 2. definition of perpendicular
3. ∠aec ≅ ∠bdc 3. all right angles are congruent
4. ? 4. reflexive property
5. △aec ~ △bdc 5. aa similarity theorem
what is the missing statement in step 4?
a.∠ace ≅ ∠ace
b.∠eab ≅ ∠dbc
c.∠eac ≅ ∠eac
d.∠cbd ≅ ∠dbc

The reflexive property of equality states that a value is equal to itself. (i.e. for all real numbers, x = x.)

Given that the reason for the missing statement, it means that the similarlity statement is equal to it self.

Having proved in statement 3 that ∠AEC ≅ ∠BDC both being right angles, it can be seen that the angle both have in common is angle C.

Thus, to statement 4 shows that angle C is congrent to itself.

Therefore, the missing statement in step 4 is ∠ACE ≅ ∠ACE