《数学人教版八年级上册三角形全等的判定（1）.2.1全等三角形的判定(第1课时)》由会员分享，可在线阅读，更多相关《数学人教版八年级上册三角形全等的判定（1）.2.1全等三角形的判定(第1课时)（38页珍藏版）》请在金锄头文库上搜索。
1、 ,12.2.1 1, 1 2 3 ,1 ,2 ABC DEF,AB=DE, AC=DF, BC=EF, A= D, B=E, C= F, ,1.,3M,3M,1.,45?,2.,45?,:.,2.,4cm6cm ,6cm,6cm,4cm,4cm,:.,4cm,30:,4cm,4cm,30?,30?,:.,3045,:.,180, , ,3.,300,700,800,300,700,800,307080,:.,3cm4cm6cm ,ABCABCAB=AB BC=BCCA=CA.,1.AB=AB 2.A,BAC,BCC 3.BCAC.,A,B,C, SSS, ,?,ABCDEF,A,B,C,D,
2、E,F,AB=DE AC=DF BC=EF,ABCDEFSSS,ABC ABC, ABC ABC SSS, .,:,1 AB=ADBC=CD ABC ADC,A,B,C,D,AC,AC ( ),AB=AD ( ) BC=CD ( ), ABC ADCSSS,ABCADC,=,裺,.,裺, D BC BD =DC ABD ACD , ABD ACD SSS ,AB =AC AD A BC D ABD ACD ,ABDACD .,ABCDCB. AB = DC AC = DB,ABC,1.AB=CDAC=BDABCDCB,DCB,BC= CB,BF=CD,BD=CF,SSS.,3.ABCDAB=C
3、DAD=BCA=C.,ABDCDB,AB=CD ,AD=CB ,BD=DB,SSS, ABD CDB, A= C .,B,C,A,D,1ABCDEFAB=DEAC=DF = ABCDEF ,2ABACBECEAEBCD ,A,E,C,B,D,3, CBFAB =DC ,AC=DF. :ABC DCF,:,4: ,BECF , AB = DE ,AC = DF ,BE = CF . : 1ABC DEF,2,2 ABC DEF ,E, 1O OA OB CD,AOB AOB=AOB,O,D,B,C,A, 2OAOOC OAC,AOB AOB=AOB,O,C,A,O,D,B,C,A, 3CCD 2
4、 D,AOB AOB=AOB,O,D,C,A,O,D,B,C,A, 4D仭OBAOB=AOB,AOB AOB=AOB,O,D,B,C,A,O,D,B,C,A, 1O OA OB CD 2OAOOC OAC 3CCD 2 D 4D仭OBAOB=AOB,AOB AOB=AOB,1.AB=ACAE=ADBD=CE AEB ADC., BD=CE BD-ED=CE-EDBE=CD.,C,A,B,D,E,2.AC=FEBC=DEADBFAD=FBABC FDEAC=FEBC=DE,ABC FDEAB=FD.,DBABDFAD=FB, AD+DB=BF+DBAB=FD.,3.B,D,C,FBC=FDAB=EF. 1 ABCEFD 2ABCEFD.,F,A,B,C,D,E, (1) AC=ED.,(2) ABC EFD AB=EF BC=FD AC=ED ABC EFD (SSS).,1.SSS 2.,12.219 ABC EFD AB =EF AC =EDBDCF . 1SSSABCEFD 21 ABEF,
