If Δ ABC ≅ Δ ACB, then Δ ABC is isosceles with
AB and AC are the equal sides of equilateral triangle ABC because only then after reverting it to form 
ACB, the two triangles can be proved congruent.
2
If Δ ABC ≅ Δ ACB, then Δ ABC is isosceles with
AB and AC are the equal sides of equilateral triangle ABC because only then after reverting it to form ACB, the two triangles can be proved congruent.