1、专题训练(三) 全等三角形的基本模型模型一平移模型常见的平移模型:图3ZT11如图3ZT2,点B在线段AD上,BCDE,ABED,BCDB.求证:AE.图3ZT22如图3ZT3,点A,B,C,D在同一条直线上,ABCD,AEBF,CEDF.求证:AEBF.图3ZT3模型二轴对称模型常见的轴对称模型:图3ZT43如图3ZT5,BD,请添加一个条件(不得添加辅助线),使得ABCADC,并说明理由图3ZT54如图3ZT6,BDAC于点D,CEAB于点E,ADAE.求证:BECD.图3ZT65如图3ZT7,A,C,D,B四点共线,且ACBD,AB,ADEBCF.求证:DECF.图3ZT76如图3ZT8
2、,BEAC,CDAB,垂足分别为E,D,BECD.求证:ABAC.图3ZT8模型三旋转模型常见的旋转模型:图3ZT97如图3ZT10,已知ABAC,ABAC,ADAE,且ABDACE.求证:ADAE.图3ZT10模型四一线三等角模型图3ZT118如图3ZT12,B,C,E三点在同一条直线上,ACDE,ACCE,ACDB.(1)求证:BCDE;(2)若A40,求BCD的度数图3ZT12模型五综合模型平移对称模型:平移旋转模型:图3ZT13图3ZT149如图3ZT15,点B,F,C,E在同一条直线上,FBCE,ABED,ACFD,求证:ACDF.图3ZT1510如图3ZT16,ABBC,BDCE,
3、ABBC,CEBC.求证:ADBE.图3ZT16详解详析1证明:BCDE,ABCD.在ABC和EDB中,ABDE,ABCD,BCDB,ABCEDB(S.A.S.),AE.2证明:AEBF,AFBD.CEDF,DACE.ABCD,ABBCCDBC,即ACBD.在ACE和BDF中,AFBD,ACBD,DACE,ACEABDF(A.S.A.),AEBF.3解:答案不唯一,如添加BACDAC.理由:在ABC和ADC,BD,BACDAC,ACAC,ABCADC(A.A.S.)4证明:BDAC,CEAB,ADBAEC90.在ADB和AEC中,ADBAEC,ADAE,AA,ADBAEC(A.S.A.),AB
4、AC.又ADAE,ABAEACAD,即BECD.5证明:ACBD,ACCDBDCD,即ADBC.在AED和BFC中,AB,ADBC,ADEBCF,AEDBFC(A.S.A.),DECF.6证明:BEAC,CDAB,BEACDA90.又AA,BECD,ABEACD,ABAC.7证明:ABAC,ADAE,BACDAE90.BACDACDAEDAC,即BADCAE.在ABD和ACE中,BADCAE,ABAC,ABDACE,ABDACE,ADAE.8解:(1)证明:ACDE,ACBE,ACDD.ACDB,DB.在ABC和CDE中,ACBE,BD,ACCE,ABCCDE(A.A.S.),BCDE.(2)ABCCDE,ADCE40,BCD18040140.9证明:FBCE,FBFCCEFC,BCEF.ABED,ACFD,BE,ACBDFE.在ABC和DEF中,BE,BCEF,ACBDFE,ABCDEF(A.S.A.),ACDF.10证明:设 AD,BE交于点F.ABBC,CEBC,ABDC90.在ABD和BCE中,ABBC,ABDC,BDCE,ABDBCE,ACBE.CBEABE90,AABE90,则AFB90,ADBE.12