Q8 of 76 Page 11

In a Δ ABC, if AB = AC and BC is produced to D such that ∠ACD =100°, then ∠A =

∠ACB + ∠ACD = 180°

On solving we get,


∠ACB = 80°


∠ABC = ∠ACB = 80° (Angles opposite to equal sides are equal)


In ABC,


∠A + ∠B + ∠C= 180°


∠A + 80° + 80° = 180°


∠A = 20°

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