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nguyenphuockimhan
2 năm trước
Cho ∆ABC vuông tại A và có góc B=30°, đường cao AH 1) Chứng mình ∆ACB đồng dạng với ∆HCA 2) tia phân giác của góc ACB cắt AH tại I và cắt AB tại K Chứng minh: AC mũ 2 = AK×AB 3) Chứng minh HI÷IA=AK÷KB 4) Chứng minh Diện tích ∆ABC= 12×diện tích ∆HCI 5) Gọi M là trung bình BC. Chứng minh ∆MIK đều Cảm ơn đã giúp
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