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quynhanh2011
2 năm trước
Cho tam giác ABC nhọn và cân tại A, đường cao AH (H∈BC). a/ Hai tam giác ABH và ACH có bằng nhau không? Vì sao? b/ Tia AH có phải là tia phân giác của góc BAC không? Vì sao? c/ Kẻ tia phân giác BK (K ∈ AC) của góc ABC. Gọi O là giao điểm của AH và BK. Chứng minh rằng CO là tia phân giác của góc ACB.
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