Question

If BC = AB and angle B is 80° in triangle ABC then find angle A

Answer 1

Answer:

Step-by-step explanation:in ΔABC

BC=AB

∴∠BAC=∠BCA  {angles opposite to equal sides}

let ∠BAC=∠BCA=x

in ΔABC

∠BAC+∠BCA+∠ABC=180° {angle sum property of Δ}

⇒x+x+80°=180°

⇒2x=180°-80°

⇒2x=100°

⇒x=100°/2

⇒x=50°

∴∠BAC=50°