内容正文:
{#{QQABRYKQogCgAgBAAAgCQwXCCkIQkACACKoGgBAMsAAAQBNABAA=}#}
{#{QQABRYKQogCgAgBAAAgCQwXCCkIQkACACKoGgBAMsAAAQBNABAA=}#}
AB=CE.
12.解:(1)如图所示,△A1BC即为所求,
在△ABC与△CED中,
∠CAB=∠DCE,
AC=CD.
.△ABC2△CED(SAS),
.∠B=∠E
BE-CD.
13.(1)证明:在△BEF与△CDA中,
∠B=∠ACD,
-5
BF-CA.
由图知,A的坐标为(1,一1),B的坐标为(4,一2),C的
∴.△BEF≌△CDA(SAS),.AD=EF
坐标为(3.一4).
(2)解:,'△BEF≌△CDA,∴.∠D=∠BEF.
(2)如图所示,点P即为所求.
∠D=78°,∴∠BEF=78
13.证明:(1),AD是EF的垂直平分线,
EF∥AC..∠BAC=∠BEF=78
..DE-DF.
14.证明:(1)∠ABC=∠DBE,·∠ABC+∠CBE=
DE⊥AB,DF⊥AC
∠DBE+∠CBE,即∠ABE=∠CBD
.AD平分∠BAC
AB=CB.
(2):∠BAC=60°,AD平分∠BAC
在△ABE和△CBD中,
∠ABE=∠CBD.
BE=BD.
:∠EAD-文∠BAC-30
△ABE≌△CBD(SAS),
,DE⊥AB.AD⊥EF
..AE=CD.
∴.∠EAD十∠AEG■∠DEG+∠AEG=90°,
(2)'△ABE2△CBD
∴.∠DEG=∠EAD=30°,
.∠BAE=∠BCD.
∴.DE=2DG
'∠NMC=180°-∠BCD-∠CNM,∠ABC=180°-
14.(1)证明::△ABC为等边三角形,
∠BAE-∠ANB.
.AB=BC=AC,∠ABC=∠ACB=∠BAC=60.
又∠CNM=∠ANB,∠ABC=90°,
AB=CA.
.∠NMC=90,.AELCD.
在△ABE和△CAD中,∠BAC=∠C.
(3)如图,作BK⊥AE于点K,BJ⊥
AE-CD.
CD于点J.
∴△ABE≌△CAD(SAS).∴.∠ABE=∠CAD.
,△ABE≌△CBD,
(2)解::∠ABE=∠CAD,∠BAD+∠CAD=60°
.AE=CD,Sar=SAcm·
.∠BAD+∠ABE=60°,
“7AE,BK=2CD·B,
∴.∠BPD=∠ABE+∠BAD=6O
:BQ⊥AD,∴∠PBQ=90-∠BPD=30°,
:BK=BJ.
.BP=2PQ=6,.BE=BP+PE=6+1=7.
BK⊥AE.BJ⊥CD.
期中综合评价
.MB平分∠AMD.
1.C2.C3.C4.B5.A6.D7.D8.B9.C10.C
第十三章随堂练
11.A12.A13.C14.B15.B16.C
1.C2.B3.A4.C5.D6.D7.D
17.(-2,-3)
8.(-3,-5)
18.(1)SAS(2)∠ACB=2∠ABC
9.55°,55或70.40
19.减少10
10.3
20.证明:(1),AB=AD,,.∠ABC=∠ADB.,AD=CD,
11.(1)30(2)3
∴.∠DAC-∠C.:∠ADB=∠DAC+∠C-2∠C.
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