In ∆ ABC, ∠B = 70° and ∠C = 60°. The internal

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In ∆ ABC, ∠B = 70° and ∠C = 60°. The internal bisectors of the two smallest angles of ∆ ABC meet at O. The angle so formed at O is

1. 125°
2. 120°
3. 115°
4. 110°

Correct Option: A

We draw a figure triangle ABC in which the internal bisectors of the two smallest angles of ∆ ABC meet at O ,

Given , ∠B = 70° ; ∠C = 60°
We know that , ∠A + ∠B + ∠C = 180°
∴ ∠A = 180° – 70° – 60° = 50°
According to the question,
∠OAC = 25° ;
∠OCA = 30°
∴ ∠AOC = 180° – 25° – 30° = 125°