Question

ΔABC is an isosceles triangle with AB = AC and ∠B = 85°, then find ∠A.

Answer 1

Here ΔABC is isosceles, and also given that AB = AC.
∠B = ∠C ......(isosceles triangle property)

∠A + ∠B + ∠C = 180°....... (1)
∠B = ∠C = 85°

So, quation (1) can be written as,
∠C = 180° - 85° + 85°
= 180° - 170°
= 10°