Question

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
Line segment BD is an angle bisector of ∡ABC.

by Construction


Definition of an Angle Bisector
Line segment BD≅ Line segment BD

Reflexive Property
TriangleABD ≅ TriangleCBD

Side-Angle-Side (SAS) Postulate
∡BAC ≅ ∡BCA

CPCTC

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

∡ABD ≅ ∡DBC

∡BDA ≅ ∡BDC