Respuesta :
Answer:
The missing reason in step 5 is;
The linear pair postulate
Step-by-step explanation:
The information given are;
Column 1, Column 2
Statements, Reasons
Line AB intersect DE at C, Given
∠DCB and ∠BCE are linear pair, Definition of linear pair
∠DCB is supplementary to ∠BCE, Linear pair postulate
∠BCE and ∠ECA are linear pair, Definition of linear pair
∠BCE is supplementary to ∠ECA, Linear pair postulate
∠DCB ≅ ∠ECA, Congruent to supplementary theorem
Therefore, the missing reason in step 5 is the linear pair postulate.