Question

In a ∆ABC, if AB = AC and ∠B = 65°, find ∠A.

Answer 1

In $△ABC$, we have:
AB = AC
$\angle B=65°$
Since ABC is an isosceles triangle, we have:
$\angle C=\angle B$
$\angle C=65°$
In triangle ABC, we have:
$$\begin{gathered} \angle A+\angle B+\angle C=180° \\ \Rightarrow \angle A+65+65=180° \\ \Rightarrow \angle A=180°-130° \\ \therefore \angle A=50° \end{gathered}$$