Given: ∠ABR and ∠ACR are right angles
Line segment AB is congruent to line segment BC. Line segment BC is congruent to line segment AC.
Prove: Line AR bisects Angle BAC.
Triangles ABR and ACR share side AR. A line is drawn from point B to point C and intersects side AR at point P.
It is given that ∠ABR and ∠ACR are right angles, AB ≅ BC, and BC ≅ AC. Since they contain right angles, ΔABR and ΔACR are right triangles. The right triangles share hypotenuse AR, and the reflexive property justifies that AR ≅ AR. Since AB ≅ AC, the transitive property justifies that AB ≅ AC. Now, the hypotenuse and leg of right ΔABR is congruent to the hypotenuse and the leg of right ΔACR, so ΔABR ≅ ΔACR by the HL congruence postulate. Therefore, ∠ABR ≅ ∠ACR by CPCTC, and AR bisects ∠BAC by the definition of bisector.