Question

11.
If in AABC, AB – AC, LA = 40° then C.
(A) 70°
(B) 50
(C) 90°
(D) 60°​

Answer 1

Answer:

In a triangle ABC, AB = AC, ∠BAC = 40° then the external angle at B is :

A) 90°

B) 70°

C) 110°

D) 80°

Correct Answer:

C) 110°

Description for Correct answer:

According to question

Given:

∠A=40∘ AB=AC

∴∠B=∠C

In△ABC

∠A+∠B+∠C=180∘

40∘+2∠B=180∘

2∠B=180∘−40∘

2∠B=140∘

∠B=70∘

∴ External angle at B=180∘−70=110∘