Given that angles A, B, C of a triangle ABC equal to each other.
We have to prove that ΔABC is equilateral
We have, ∠A = ∠B = ∠C
Now,
∠A = ∠B ⇒ BC = AC
[Opposite sides to equal angles are equal]
and ∠B = ∠C ⇒ AC = AB
From the above we get
AB = BC = AC
⇒ ΔABC is equilateral