Question

已知点o是三角形ABC的内心,求角BOC与角A的关系

Answer 1

∠BOC=180°-∠OBC-∠OCB

=180°-∠ABC/2-∠ACB/2

=180°-(∠ABC+∠ACB)/2

=180°-(180°-∠A)/2

=90°+∠A/2

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