Cho tam giác ABC vuông tại A có AB = 6cm, AC = 8cm , BC = 10cm . Đường cao AH (H thuộc BC); Tia phân giác góc A cắt BC tại D. a/ Chứng minh tam giác ABC đồng dạng tam giác HAC. b/ Chứng minh `AB^2 = BC.HC` c/Vẽ đường thẳng vuông góc với AC tại C cắt đường phân giác AD tại E . Chứng minh tam giác ABD đồng dạng tam giác ECD Chỉ cần làm câu b,c ( vẽ hình )

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