Question

In triangle ABC if AB=AC and angle B = 50° then find angle A

Answer 1

Given that AB=AC
and <B=50

If adjacent sides are equal, then the angles opposite to equal sides are also equal.

by this <C=50°

Angle sum property <A+<B+<C =180°
by calculation
50+50+x=180. let angle A is x
x=80°

Therefore <A=80°

Answer 2

so here the answer

AB=AC,<B=50°

<C=<B (angle opposite to equal side of an isosceles triangle are equal)

then by angle sum property

<A+<B+<C=180°

<A+<B+<B=180° (<C=<B)

<A+50°+50°=180°

<A+100°=180°

<A=180°-100°

<A=80°