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解ï¼1).设åçç´å¾ä¸ºdï¼å 为ABæ¯ç´å¾ï¼æ
AB=d,ï¼AE/BE=1/4ï¼æ
AE=d/5ï¼BE=4d/5ï¼
â ACBæ¯ç´å¾ä¸çåå¨è§ï¼æ
â ACB=90°ï¼CDâ¥ABï¼æ
CEæ¯RTâ³ABCæè¾¹ä¸çé«ï¼
AC²=AEÃAB=(d/5)Ãd=d²/5ï¼æ
AC=d/â5=(â5/5)d.
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2).RTâ³AEHï½RTâ³AFBï¼AH/AB=AE/AFï¼â´AHÃAF=ABÃAE=dÃ(d/5)=d²/5
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