Question

ABC is a triangle in which AB = AC and angle OBC = angle OCB
prove that triangle ABO is congruent to triangle ACO

Answer 1

If AB = AC , then angle ABC is equal to angle ACB ( isoceles triangle )
Angle OBC = Angle OCB ( given )
Angle ABC - Angle OBC = Angle ACB - Angle OCB ( proved equal )
Thus, Angle ABO = Angle ACO.