Given: ΔABC is an isosceles triangle where AB = BC. Prove: m∠BAC = m∠BCA

Proof:
Statement Reason
1. Let ΔABC be an isosceles triangle where AB = BC. given
2. Create point D on so that bisects ∠ABC as shown. constructing an angle bisector
3. m∠ABD = m∠DBC definition of angle bisector
4. BD = BD
5. ΔABD ≅ ΔCBD SAS
6. m∠BAC = m∠BCA Corresponding angles of congruent triangles are equal.
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What is the reason for statement 4 in this proof?
A.
Transitive Property of Equality
B.
definition of midpoint
C.
definition of parallel lines
D.
Reflexive Property of Equality