In ΔABC shown below, line segment AB is congruent to line segment BC:

Triangle ABC, where sides AB and CB are congruent

Given: line segment AB≅line segment BC

Prove: The base angles of an isosceles triangle are congruent.

The two-column proof with missing statement proves the base angles of an isosceles triangle are congruent:

Statement Reason

1. segment BD is an angle bisector of ∠ABC. 1. by Construction

2. ∠ABD ≅ ∠CBD 2. Definition of an Angle Bisector

3. segment BD ≅ segment BD 3. Reflexive Property

4. 4. Side-Angle-Side (SAS) Postulate

5. ∠BAC ≅ ∠BCA 5. CPCTC

Which statement can be used to fill in the numbered blank space?

ΔDAB ≅ ΔDBC

ΔABD ≅ ΔABC

ΔABC ≅ ΔCBD

ΔABD ≅ ΔCBD