Question

L ACD is an exterior angle ABC .The measure of LA AND LB are equal. If m L ACD=130,find the m LB

Answer 1

An exterior angle of a triangle is equal to the sum of the opposite interior angles.

Hence, In this case ∠A and ∠B

So,

∠A+∠B=140 ∘

as ∠A=∠Bor,

2∠A=140 ∘

∠A=∠B=70 ∘