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buithiha7789
2 năm trước
Cho đoạn thẳng AB có O là trung điểm của AB. Trên cùng nửa mặt phẳng bờ AB vẽ Ax vuông góc với AB , By vuông góc với AB . Qua O kẻ đường thẳng Vuông góc với OC cắt By tại D với C thuộc Ax. OH vuông góc với CD tại H a, CM $\frac{OC^2}{OD^2}$ = $\frac{HC}{HD}$ b, CM tam giác AHB vuông tại H
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