AB is congruent AC - Definition of an Isosceles triangle
BX is congruent to XC - Definition of a bisector
AX = AX - Reflexive property of equality (draw lines over the AX)
AX congruent to AX - definition of congruent.
Triangle ABX congruent to triangle ACX - SSS
Angle BAX congruent angle CAX - CPCTC (corresponding parts of congruent triangles are congruent
AX bisects angle BAC - Definition of angle bisector.
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