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thaynhoinhoi
2 năm trước
Cho đường tròn tâm O đường kính AB =2R và C là một điểm nằm trên đường tròn sao cho CA > CB. Gọi I là trung điểm của OA. Vẽ đường thẳng d vuông góc với AB tại I cắt tia BC tại M và cắt đoạn AC tại P; AM cắt (O) tại điểm thứ hai là K. a) Chứng minh tứ giác BCPI nội tiếp được trong một đường tròn b) Chứng minh ba điểm B, P, K thẳng hàng c) Các tiếp tuyến tại A và C của đường tròn tâm O cắt nhau tại Q . Tính diện tích tứ giác QAIM theo R khi BC=R.
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