In a triangle Δ ABC, AB = AC and ∠A = 80°, then find ∠B.

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Accepted Answer

Given that AB = AC, triangle ABC is isosceles with AB = AC. Therefore, angles opposite these sides are equal, so ∠B = ∠C.

The sum of angles in a triangle is 180°:
∠A + ∠B + ∠C = 180°
Given ∠A = 80°, and ∠B = ∠C = x,
So, 80° + x + x = 180°
=> 80° + 2x = 180°
=> 2x = 100°
=> x = 50°

Therefore, ∠B = 50°.

Answer

Answer

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