∠BOC =180°-(∠OBC+∠OCB) =180°-(1/2∠ABC+1/2∠ACB) =180°-1/2(∠ABC+∠ACB) =180°-1/2(180°-∠A) =90°+1/2∠A 132=90+∠A/2 ∠A=84°
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