ABDADDDDDDDDDDDDDDDDDAOBDDDDDAOBDDDDDODDD1DDODDDDDDDDDDDDDODDOADOBDMDNDD2DDDDMDNDDDDDD1MNDDDDDDDDDDD2DDDDDDDDD角平分线的性质[问题]DDDDDDDDDDDDDDDDDDDDDDDDDACDDDDDAB=ADDBC=DCDDDADDDDDDDAEDAEDDDDDDDDDDDDDDDDD［操作］DAOBDDDDDCDD3DDDDOCDDDOCDDDDDDDDDDDDDDAOBDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD[DD]ODDOCDDAOBDDDDDDDDDPD=PEODD[DDDDDD]PDZAOBDDDDDPD丄OADDDPE丄OBDE:.PD=PE0地世也驭覚也如叽哑应DD1DDDDDDSDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDPDOCDDPDDOADEDOCODDPDODDDDDDDFDEFDDDFDEFDDDDDDDDDDDD【例2】DDDDABCDDDDDBMDCNDDDDPDDDDDODDABDBCDCADDDDDDP【例3】叮DDAABCODDZACEDDDDDDDDFDDE丄BCDEODDBCDDDDDEDODDCE=CFDDF丄ACD【例4】ODDADDDABCDDDDDDDDEDFDBD=CDDDDDDB=DCDDEDABDDFDACDDDD例5】ODDDDABCDDDDAC=BCDDC=9O°0ADDDABCDDDDDDDEDABDODDEDDDDAB=AC+CDD例6】ODDOCDDAOBDDDDDDPDOCDDDDPDDOAODDDDPEDOBODDEDFDDDDDD1DDDDDDDB叮D1DDD1DD2DDD2DDD3叮4DDCD90°DDDDDDDDDDDDDDDDDODDOCODD.AOBDDPDDDEODDOCDOADOBDDDDPD=PEDODDPDOCDDPDDOADPEDOBDDDPD=PEDODDPDOCDDPDDOADPEDOBDDOCODDAOBDDDPD=PEDAD0DBD1DCD2DDD3D2DDDDDDDDDDDDDDDDDDD3DABCODDACB=9O°0ADODDBACDBCDDDDEDDABDEDDDDDDDDE=1.5cm叮BC=DAD3cmBD7.5cmCD6cmDD4.5cm4DDDDOPODDAOB[\PC[\OAQCDPDROBDDQDDDDDDDDDADPCDPDBDOCODCDaCPOaaDPODDOCPC2DDDD5DDDDDCQ90°OADODDBACaBCaDQDBC5cmaBADDDCAODDBCDDDACDDBDWAD5cmBD3cmCD2cmDDDDDD6DDDDDABCODDBDDCDDDDDDDODODDABDDDOEDACDEDDODDOEDDDDDDDDADODDOEBDODDOECDODDOEDDDDDD7DODDABDCDDODDBAC叮ACDDDDDDDDOEDACDACDEDDOE=2DDABDCDDBDODDADCDDDDDDDDDDDDD00000008DODDABWA^DDABCDDADO\90°DDDACODDADDDBDODDCDODDDDODD1求证ZOCD=2ZA(3).与R,AB=7,BC=8,AC=9(1.)求BP、CQ、AR的长。(2).如图2若CD丄BO于D如图3若BO的延长线叫AC于E,CO的延长线叫AB于F,若ZA=60°,求证:OE=OF.第6题）第7题）第8题）DDDDDD3D第十讲角平DDEDPD=PEU【例BD=CDDBFDACDCEDABDDDDDDBACDDDDD【例3】DDDDCABDDDDDDDACBDDDDDDDPDDBPDDDCBN分线的判定［思考］角平分线上的点到角两边的距离相等，这里的条件是；结论是如果将条件和结论互换，则可以得到命题，那么，这个命题是真命题吗？可以证明吗？DD1DDDDDDODDPDDOADPEDOBDDDDDDDDDDPDDAOBDDDDDD004D□□□□□BDDABCDAB=BCDDPDBDDDPMDADDPNDCDDMDN【思考】DOCDDAOBDDDDDD□□5DDDDDDABCDDDDBCDDDDEGDACDACDDDDGDDDDBF=CGD【例5】如图,在ZBAC的平分线上任取一点D,在AB,AC上各到一点E和F,若DE=DF,且AE>AF,求证ZAED+ZAFD=180°DDDDDDDPM=PNUADDEDBCDBACDDAEDEDEFDABDFDPDDOADDPEDOBDEDDDDDDDDP=PEDACD+UABD=180°DDDCD=DB【例6】ODDDDDEAFDDDDDDDDDD课后作业】DD1DD3、DDDDDABDCDDDPDDDMNDDDDD1、DDDDDPAWONDADPBWOMDBDDPADPBDDMOM50°叮OPCD30°DDDPCADDODABDBCDDDDDDDDDDAOCDDDD5DD2010DDDDDDDDDDPDBCDBDWCEDDDDDDDDDDDDDDDDDD4DDDDDDDDD2DDMMCDDDPDBCDDDDD-DDDPDDDDDDABCDDDDDDAEDDDDDDDPDDDDDDDDDDDDRtiABCODDAD90°口BDODDABCDDACDDDDDABD4DBDW5DADD3DDDDDBCDDDDDD4DDDD3DDDD5DD6DDDDDDABCDDDCD90°口ADDDDDDDDDDDDEWABDEDDDDDDDDDDADBDWDEBCBDDEODDADBCDADODDEDCDDACDAE7DDDDDDDDABCDDABDACDADDDABCDDDDDDDEABDDH\ACDDDDDD曰FDDDDDDDDDDDDDADDAODDEDFBDAEDAFCDADDDDDPDABDACDDDDDDDABDACDDDDADDDDDD8DDDDDDADODDBACDDEWABDDDD曰DH\ACDDDDFDDDDDDDDAEGDDDAFGDDDAEDDDAFDDDDDEGDDDFGDDDBDEDDCDFDDDDDDDDCD3DDD4DBD2DAD1DDD6DDDD7DDDD8DD(□9DODD/』l2Dl3DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDADCD3D1DDD4DBD2D10、DDDDBDDCD90°口MDBCDDDDDABDD2DDDMODDAMODDADCDDDDD1DCAD\^WCDA\ACDBDWEDBCDDDEWECDDDDADODDBAE.11、DDDDDD12DDDDAEDBDDDABMODDAE,BDODDD1DBC=2ADD2DAB=AE+CED3DEDODDBDMCDDAE=BEDBDODDABMDDD13DDDDDDDDDDDDDDDBDDDDD-1D0DDDCDDDDD1D0DDDDDyDDDDDDADDDDDDDDDDDDBAC=2DBDODDDDDMDACDMD1DDDDDABD=DACDD2DDEDBADDDDDDDD:ADODDCAED3叮ADDDDDAC-ABAM000000000000000000000000000
