AD is congruent to AD

BD is congruent to DC

AD is the perpendicular bisector of BC

angle ADB is congruent to angle ADC

All right angles are equal

Perpendicular lines form right angles

SAS (Side-Angle-Side)

Given

CPCTC

Reflexive

AB is congruent to AC

angle ADB and angle ADC are right angles

Triangle ABD is congruent to Triangle ACD

Triangle ABC is Isosceles

Definition

Definition