12.2, ,1 ,1. ,.,3.ABC DEF.,AB=DE, CA=FD, BC=EF, A= D, B=E, C= F,.,2. ,AB=DE, CA=FD, BC=EF, A= D, B=E, C= F,1.ABCDEF,2.ABCDEF?,3M,3M, 1 ,45?,45?,2 ,.,4cm6cm ,6cm,6cm,4cm,4cm,4cm,30:,4cm,4cm,30?,30?,3045,.,2ABCDEF ,DE=AB , EF=BC, DF=AC.,D,E,F, , 1BC=BC 2E,FAB,ACD 3DE,DF.,14cm5cm6cm, SSS,ABC DEF, ABC DEFSSS., AB =AC AD A BC D ABD ACD ,AB=AC,AD,BD=CD,DBC, D BC BD =DC ABD ACD , ABD ACD SSS ,(1) AD=FB AD+DB=FB+DB. AB=FD ABCFDE ,AC=FE BC=DE AB=FD ABCFDESSS,1 AC=FEAD=FB,BC=DE. (1)ABCFDE; (2) AC FE,=,=,?,?,2 ABCFDE., A=F., AC FE.,2., SSS),1. . 2. .,12.2121015,1067,