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三角形abc的角b、角c的外角平分线交于点o,则角boc等于多少?(答案与角a有关)
人气:275 ℃ 时间:2020-04-02 16:54:54
解答
∠BOC=90°-1/2∠A
证明:∠BOC=180°-(∠OBC+∠OCB)
=180°-(1/2(∠180°-∠ABC)+1/2(∠180°-∠ACB))
=180°-180°+1/2(∠ABC+∠ACB)
=1/2(180°-∠A)
=90°-1/2∠A
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