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[几何] 复杂平面几何

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大佬最帅 Posted 2021-10-10 09:19 |Read mode
mmexport1633828725292_edit_153787071919241.jpg
如何证明此复杂几何题

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乌贼 Posted 2021-10-11 01:57
211.png
就是求证$ KSTL $四点共圆

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 Author| 大佬最帅 Posted 2021-10-11 06:46
回复 2# 乌贼
证完之后竟未发现特殊性质

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乌贼 Posted 2021-10-13 17:03
根据三圆根轴三线共点或平行,必然有上述四点共圆。可是我也没证出来

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乌贼 Posted 2021-10-16 05:06
回复 3# 大佬最帅
没发现什么特殊性质,倒是发现一般规律,即
$ Q,R $为$ \triangle ABC $内两点,$ BQRC $四点共圆,$ K,L $为$ \odot AQR $上任意两点,$ H $为$ KR $与$ LQ $的交点,$ \odot BKR $,$ \odot CLQ $分别与$ \odot ABC $交于$ S,T $,$ P,M $为$ \odot BKR $与$ \odot CLQ $的交点,$ X $为$ \odot KHS $与$ \odot LHT $的另一交点。求证:$ P,H,X,M $四点共线。
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