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Bài 2. Cho tam giác ABC có AB = AC = 5cm;BC = 8cm. Kẻ AH vuông góc BC (H thuộc BC) a) Chứng minh: AH là đường trung trực của BC (2 cách) b) Tính độ dài đoạn AH c) Kẻ HD vuông góc AB (Dthuộc AB); HE 1 AC (E thuộc AC). Chứng minh AH là đường trung trực của DE (3 cách – nếu có thể) Các ANH CHỊ GIÚP EM VỚI Ạ
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