Question

If each of the two equal angles of an isosceles triangle is 68°, find the third angle.

Answer 1

Let Δ ABC is an isosceles triangle

∴ In Δ ABC, AB = AC

and ∠B = ∠C = 68°

But ∠A + ∠B + ∠C = 108°  ...(Sum of angles of a triangle) 

⇒ ∠A +  68° + 68° = 180°

⇒ ∠A + 136° = 180°

⇒ ∠A = 180° - 136°

∴ ∠A = 44°

Hence third angle = 44°