Example 1: For Δ ABC, show that AB = AC and Δ ABC is isosceles if the bisector AD of ∠ A is perpendicular to side BC. Also, this condition satisfies the properties of the isosceles triangles.
thus, Δ ABC is an isosceles triangle.
Example 2: Prove that △ACF≅△AEB, if ∠C=∠E and AC=AE.