Q4 of 35 Page 184

In Fig. 10.38, ∠ ABC = 69°, ∠ ACB = 31°, find ∠ BDC.

∠BAC = ∠BDC (Angles in the segment of the circle)

In triangle ABC,


∠BAC + ∠ABC + ∠ACB = 180o (Sum of all angles in a triangle)


∠BAC + 69o + 31o = 180o


∠BAC = 180o – 100o


∠BAC = 80o


Thus,


∠BDC = 80o


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