Question

show tha isosceles triangles, angles opposite to equal side are equal

Answer 1

Given: ABC isosceles triangle

i.e. AB=AB

To prove: angleB=angleC

Construction: Draw a bisector of angle A intersecting BC at D.

Proof: In triangle BAD & triangle CAD

AB=AC        {Given}

angle BAD= angle CAD   {By Construction}

AD=AD           {common}

therefore, triangle BAD is congruent to triangle CAD    {SAS rule}

Thus,

angle ABD=angle ACD               {CPCT}

==> angle B= angle C

Hence proved.

Hope it helps u.