2022年海淀区中考压轴题多解研究.pdf

20XX 年海淀区中考压轴题多解研究2006?6?9?n? ?2?a?065?(163100)? ?1,?O ?AB?GCD? E,?AD?2OC?2OD,?nOD =5. (1)?sinBAD= 3 5 , ?CD?; (2)?ADO!EDO=4!1,? OAC(?1)?(?). ?,?)?,?C ?C?,?,?2?,?2? ?G?1?;?E ?9?,?.? ?9?.?3? ?:?,?F?,?C?7?#?5 ?1,?b;?B?F?,?#?7?# ?5?1.?O,?F?C?a.? ?,?2000?a? 7?8#?x?i?. (1)?CD?: ?:?1. ?AB?O?,?ADB=9076. 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 1 页，共 16 页?OD=5,?AB=10. ?bRt%ABD?,sinBAD= BD AB , ?sinBAD= 3 5 , ? BD 10 = 3 5 ,?BD=6, AD=AB 2 -BD 2 =10 2 -6 2 =8. ?DB=76,B&D, ?D7AB=D7ABD,=D, ?DE(10=8(6,?DE= 24 5 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 2 页，共 16 页, ?CD=2DE= 48 5 . ?:?1. ?,AD=8. ?bRt%ADE?,sinDAE= DE AD = DE 8 . ?sinBAD= 3 5 , ?sinDAE=sinBAD, ? DE 8 = 3 5 ,?DE= 24 5 , ?CD=2DE= 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 3 页，共 16 页48 5 . ?,:?1. ?OE=x,?#BE=5-x. ?bRt%OED?, DE 2 =OD 2 -OE 2 =5 2 -x 2 . ?bRt%BED?, DE 2 =BD 2 -BE 2 =6 2 -(5-x) 2 , ?5 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 4 页，共 16 页2 -x 2 =6 2 -(5-x) 2 , ?x= 7 5 . ?DE=OD 2 -OE 2 =5 2 -( 7 5 ) 2 = 24 5 . ?CD=2ED= 48 5 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 5 页，共 16 页. ?:?1. ?,?,OE= 7 5 , ?=O+O=5+ 5 , 7A7A ?1?!?(?%?) A90AC EAACEE AEAE 7 2 BE=BO-OE=5- 7 5 , ?G?1?,DE 2 =AE7ABE, ?DE 2 =(5+ 7 5 )(5- 7 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 6 页，共 16 页5 )= 576 25 . ?DE= 24 5 (?8?C?), ?CD=2DE= 48 5 . ?:?2. ?O?OF&AD? F. ?AB?O?, ?BD&AD, ?OF)BD, ?,BD=6. ?AO=OB,?AF=FD, ?OF= 1 2 BD=3. ?,AD=8. ?S%OAD= 1 2 OF7AAD= 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 7 页，共 16 页1 2 (3(8=12, ?S%OAD= 1 2 AO7ADE= 1 2 (5(DE = 5 2 DE, ? 5 2 DE=12,?OE= 24 5 , ?CD=2ED= 48 5 . ?:?1. ?,AB=10,BD=6,AD=8. ?DE?Rt%ABD?AB?O?, ?Rt%AED74Rt%ADB, ? 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 8 页，共 16 页DE BD = AD AB , ? DE 6 = 8 10 ,?DE= 24 5 , ?D=D= 48 5 ?6?3 ?G?BD?,? ?EG . ?EG?Rt%BDE ?BD?, ?EG= 1 2 BD=3. ?i?%GDE?2%OAD? ?,?. 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 9 页，共 16 页?GDE? 1 2 BC?2OAD? 1 2 BD, ?BBC=BD, ?GDE=OAD, ?%GDE74%OAD, ? DE AD = EG OD . ?AD=8,OD=5, ?DE= 3(8 5 = 24 5 , ?CD=2ED= 48 5 . ?:?4,?BC. 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 10 页，共 16 页?BE?CD? ?1?, ?BC=BD,? %BCD?,?. ?OA=OD,? %OAD?,?. ?BCD?BD,OAD? 1 2 BD, ?BCD=OAD, ?%BCD74%OAD, ? CD AD = BO OD , ?AD=8,BD=6,OD=5, ?CD= 6(8 5 = 48 5 . (2)?OAC(?1)?: ?:?1. ?B?O?,B&D, 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 11 页，共 16 页?B=BD,=D, 7A37A 2007?3?8 C2E. :. AAC CACA BAD=CDB,AOC=AOD. ?AO=DO,?BAD=ADO. ?ADO=4x,?#CDB=4x, ?ADO!EDO=4!1, ?#EDO=x. ?ADO+EDO+EDB=9076, ?4x+4x+x=9076, ?x=1076, ?AOD=18076-(OAD+ADO) =10076, ?AOC=AOD=10076. ?S?OAC= 100 360 (5 2 = 125 18 . ?:?1. ?,EDO=1076, ?bRt%DEO?,DOE=9076-1076=8076, 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 12 页，共 16 页?S?BOD= 80 360 (5 2 = 50 9 , ?S?BOC=S?BOD= 50 9 . ?S?O= 1 2 S= 1 2 (5 2 = 25 2 , S?OAC=S?O-S?BOC, ?S?OAC= 25 2 - 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 13 页，共 16 页50 9 = 125 18 . ?,:?1. ?ADO=OAD, ?EOD=2ADO. ?ADO!EDO=4!1, ?EOD!EDO=8!1. ?EOD+EDO=9076, ?EOD= 8 9 (9076=8076. ?COD=2EOD=16076, ?COD=36076-16076=20076. ?S?CAD= 200 360 (5 2 = 125 9 , ?S?OAC= 1 2 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 14 页，共 16 页S?CAD= 1 2 ( 125 9 = 125 18 . (?%?,) ?&? ?)?D? ?4?2?0?,?(054000)?&? ?b?%?,?,?,? ?b?,?a?b,?D? ?.?,?ba?2b?2c?2d?1? ?,?#a7Ab=c7Ad?!b 2 =a7Ac? ?E?,?E.?. ?D?E?=?%?:?1 ?E?E,?a7Ab=c7Ad a c = da = c ,? 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 15 页，共 16 页2 =7A b = c ?! b = a ; ?D?&?F?d?,?,?E ?1?,?F?,? ?=?a?b,?i?D.? ?,?.?%?:?1?E?E,? ?&?,?;?=?a?b,?1? ?E?!?E,?.?A?D. ?2?,?&? ?1?1?,?%ABC?, ?,ACB=9076,CD?AB?O?.? ?: ()?O?F?b?O? ?5?,? 7A7A ?1?!?(?%?) bdb bac abcb1 4 精选学习资料 - - - - - - - - - 名师归纳总结 - - - - - - -第 16 页，共 16 页。