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pgem0171
2 năm trước
Câu 4. Cho hình chóp S ABC có đáy là tam giác ABC vuông tạiB và cạnh bên SA vuông góc với mặt phẳng đáy. a) Chứng minhBC vuông góc vs (SAB).Từ đó suy ra tam giác SBC là tam giác vuông. b) Gọi H, K, lần lượt là chân đường cao của A trên cạnh SB SC , . Điểm G là trọng tâm của tam giác SBC. Chứng minh (AHG) vuông góc (SBC) và tam giác AHK là tam giác vuông. c) Chứng minh SC vuông góc HK.
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