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Question
If ABCD is a cyclic quadrilateral in which AD || BC. Prove that ∠B = ∠C.
Solution
ABCD is a cyclic quadrilateral.
So, ∠A + ∠C = 180° ...(i)
Since AD || BC
So, ∠B + ∠A = 180° ....(ii)
From (i) and (ii)
∠A + ∠C = ∠B + ∠A
∠C = ∠B
or ∠B = ∠C
Hence proved.
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