《七年级数学下册4.3.1探索三角形全等的条件课件1新版北师大版》由会员分享,可在线阅读,更多相关《七年级数学下册4.3.1探索三角形全等的条件课件1新版北师大版(27页珍藏版)》请在金锄头文库上搜索。
1、,1,1. . 2. . 3. .,ABCDEF,AB=DE, AC=DF, BC=EF,A= B, C= F, B= E, ,1) ,(2),(3),1,2, ., .,.,?,2. ,3.,1,2,滭4cm5cm7cm.,1. AB=4cm.,:,2.A,5cm.,4. CA, CB.,3.B 7cm C,SSS,1 AB=CDBC=DAABCCDA,:ABCCDA,ABCCDA,ABCCDA,SSS,AB=CD,AD=CB,AC=CA,(),(),(),3=4 1=2 (,ABCD.,ABCD ADBC , AB=CDBC=DAABCDADBC,ABCCDA,ABCC
2、DA,SSS,AB=CD,AD=CB,AC=CA,(),(),(),1,2,3,4,1.AOBDOC,AO=DO() _=_() BO=CO() AOBDOC .,SSS,AB,DC,2.: ,AC=AD ,BC=BD ACB ADB.,A,B,C,D,ACB ADB ?,BC,BC,DCB,3, ABCDCB AB = CD AC = BD =, ABC ,SSS,AB=CDAC=BDABCDCB.,4.ACBDOAB=DCAC=DBA=D, A=D,ABCDCB,ABCDCB SSS,A=D, ,.,., ,.,?,(1),.,(2) .,(3):,SSS.,(4).,1
3、. AB=AC, BD=CD, BH=CH. ,: ABHACH, ABDACD DBHDCH,( SSS),ABHACH,2.AB=DE, BC=EF, AF=CD. (1) ABCDEF (2) A=D,:,( SSS), A=D,(),ABCDEF,AF = DC,AF+FC= DC+FC,ABCDEF,AB = DE,BC = EF,AC = DF,ABCDEF,AC=DF,1.ABCAB=ACDBCAD1ADBC2ADBAC3,: (1ADBAC (2) AD BC ,ABD ACD,AB=AC,BD=CD,AD=AD,(),(),(),ABDACD,(SSS),1,2,3,4,1=23=4,(),3+4=180,3=4=90,壩,ADBAC AD BC .,2.ADBEAD=BEAC=DFBC=EFABCDEF EABCBCEF𣿲, AD=BC(), AD+BD=BE+BD (),AB=DE,ABCDEF , ABCDEF,SSS, ABC =E ,BCEF,P105 10,AB=CD,AD=BC. AC,1 ,2 ,40o,5cm, .,1) ,(2),(3),30o 3cm,4cm6cm,30o60o,C1,C2,C,C,C1,C2, .,