Question

In triangleABC, AB = AC and angle100° then angleB = is:
2y
a) 20°
b) 40°
c) 80°
d) 60°​

Answer 1

Answer:

(b). m∠B = 40°

Step-by-step explanation:

If in ΔABC AB = AC ⇒ ∠ACB ≅ ∠ABC and m∠BAC = 100°

m∠B + m∠C + m∠A = 180°

2(m∠B) + 100° = 180° ⇒ m∠B = 40°