Question

In a triangle ABC if AB=AC and angles B=70 find angleA

Answer 1

According to isosceles triangle theorem if sides are congruent then base angle are also congruent.

Answer 2

Answer:

$\angle A=40 \degree$

Step-by-step explanation:

Given In ∆ABC ,

AB=AC and <B=70°

/* In ∆ABC , If AB=AC then <C=<B */

$Given \: \angle C=\angle B=70\degree$

$\angle A+\angle B+\angle C=180\degree$

$\implies \angle A+70 \degree+70 \degree=180 \degree$

$\implies \angle A+140\degree=180 \degree$

$\implies\angle A=180\degree-140 \degree$

$\implies \angle A=40 \degree$

Therefore,

$\angle A=40 \degree$

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