Question

Prove that, “Angles opposite to equal sides of an isosceles triangle are equal”.​

Answer 1

Consider ∆ ABC an isosceles triangle.

AB= AC

Construction: AD is bisector on BC

So, angle BAD= angle CAD

In ∆ ABD and ∆ ACD

AB=AC

angle BAD = angle CAD

AD =AD

So, ∆ABD≈∆ACD

hence, angle ABC =angle ACB. prooved