Q6 of 76 Page 10

In a Δ ABC, if AB =BC 120° and ∠B = 70°, Find ∠A.

Consider Δ ABC,

We have,


∠B = 70°


And, AB = AC


Therefore, Δ ABC is an isosceles triangle.


∠B = ∠C (Angle opposite to equal sides are equal)


∠B = ∠C = 70o


And ∠A + ∠B + ∠C = 180o (Angles of triangle)


∠A + 70o + 70o = 180o


∠A = 40o


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