专题10 几何综合压轴题(12题)

专题几何综合压轴题一解题共12小）121①CEFB

CF

2②AC)MDMDMEDE①MDEM②BMC45tanDEM2CMPEEMC3MGACH90DEM

MGCHBHM∽BHtanDEM

CH2BH

CRAB，BRCxBCxBHMBH

x

25ABCBCACBC

12

RtABCAF

AB2

BF3

AB

12

ABRtDCF2①CM②CMABAMMCAM、DCDEM

1tanEMAC3MGACBCH③90MGCHMH/AC/GMHMHGCCHDME

55DMEGMHEMHDMG∽

MGME//

MGCHMEMHBHMBCAHMBH

BC

BH

CRBCRtanABRCBMC45MCRMHBCRBMHBMRCRBCRtBH

3x5

35x5

CH

25

25x

2BH

2

135

2DE//DE

BC2①AD//ECD//FE(ADBC)②3ABCD中ABADMABBCEFMNDNEFDEFEFADECFEADCFAB/BCFDDE/DE

BC2①并BCMASAABM②DM1DECFCFEAECE

DEEF()

AD/

ADBDBDBCFDEF

DFBC2①2AFBCMAD/DFCDCFFCMCF

AFDADFMCF(ASA)AFCMEFABM//BC//ADEF②DM

1BM(AD)2

FMN1EF

DMEFMBDBAD

(33)

EF33OCDOAOBODAOBCODACBD①

ACBD

1②AMB22OABAOBCOD9030ACM

AMB的32ACM7M

DOB)BD1②DOBAMB180)∽BOD

ACOC3BDODMBODAMB90BD

3AC①40DOBOCOAOBCOA)AC

ACBD

②CAOAOBABOCAO)ABD①②40

2

BD

3RtDCO30

ODtan3

3303

OCOAAOBAOCBODAOC∽

ACOC3CAOBDODAMB)180ABMDBO903①CM

ACBD

3BDxAC3RtOCD30ODxRt307AB7AMBACBCAB(3x)

x

(2

(3)(xxAC3②M490

BD

3BDAC3xAMBACBCAB(3x)

(xxxAC3AC4AB，FDcm/sBFBF上BFGBFBFHGAGF1ABG∽EBF2HCDt3FED

2HMADMGNNBGKFHMH1111032H(2t4t)xyttyxH233y1

ABEBG2EBFABG2HMMGNAMKFHGNFGFHHMFGFN9090GFN

GFNGNFMHMABGEBF

AB2BE

AGBEFBGAN45EF

22

tANGNFMt

1tHMFNt1(2t4t)2

HCD

tt33(2tt)2

3tyt211033

Hy

13110CHH3CCH30

11303

HC(10,0)CH210HC5•ABCDADABPEt)1AD6PADEt2PAD3

PD6

AEAPBBPEBPCRt2EBCEMEADNPEEMBEABABMNANBMBE

BMMENPENNP②EBCBC3EHH，AHAB7BH7∽

AHHEAPABAP

PD

AEBPAPBAD/APBPBCEPBCCPADCDPCD

DP

(6

t565sE2EEEMMNPEEMBEABABMNRtBM

4

AEBPPABENPPEB90EBMBMEENP

MENP1NP

377

tAN

37477

②EEABHBHAHRtHEBE

7PABBHEBPAPBEAP90HAE∽

AHHE7APABtAP7t

47

61FCDEFABEADGAD180FD

EF

AGFBEEFFD

EAF45ABCDAD1F45DF2DCEAFAFGEGMG

MGDF21FGAEF

AEAGAF(SSS)45FDEFEFFGAEFBAFBAEEAF

FGBEFDEFMNGEGMGNG6EGxRtGENEG

NE

(2)

(6

xMN//CD∽AFD

MGAM6DFADDF2Cm1

MGAMDF6mmFDC27RtBCACB90BDEF2BECD1和CD2AECD3AEFMFM

22AFAB

(4

AB3图FGEF角22MMFRtBC4ACB90ABCEBDABEBDEF

ABBCABBEBCBD

AEABCDBC2CD(2ACB90AB2BCAEAF

2)

7

AEEFAE2CDCD

22

AEAEAFEF27CD142AEFCD14233EFFGEFAGBGBG2MMFMFAGEAG2

AGAG62

FM2FM28ADBADBD1EFOBDMt1EADtDM2①t②Ot1RtABDBDMDcosADB

2EEADMDDM②t0OOCDEEH/CDBDHDHDFDFtttABNNOOMMDH

21EHDO3ME

ADEDADEFOEMFEMD90

MD

)

2aDM

)

1t2bMCMDMCMMNMCMDMNCDDNMNBC//MNBDMD

)

744CMCDC

CMMDGD

)DGCDBD5DGCD

2(8)5tADEFOEMDMDMEDEDM

t

ttt

131t24②t0OABO//CDBDH

/CDOFDH

5(tEDH

DF

t4

t

809

DHDF

809

ADBABBDDHEH

FH

1123ONOMABMMADO1MADOMOAD3AN

12

AB18MN38MN()3

83

10Ot0t

809

83

109•GABCDACEGFCDF1①②

BE

:2CAG3EFADH

GEGFCD90ECG②90ECG452CG

CGCE

2//3AHG∽CHA

AGGHACCH

CDAC

AGGHAHAC1DHa3

10AHa3CH

BCA45GEBCGFCDCEGCFGCEGFECG45EGCEGF②①CEGF90

CG

2GE//

CGBECE22ACG

CECBcos45452CA

CGCACEACG∽

BECBAGAG3CEFF135

33∽CHA

AGGHAHACCHBCCDAC

AGGHACAH2AH2aAH3DHAHCHCD

DH

1032a6CH10a35510aABCDAEFG(a)ABA2ABEGDGBEaDG3AEFGEDABFDFFGBFD:34DGa2bAEFG1P

HDGABODAGDGBOGDAO90DGRtAH2AHBBH

AB

AH

72．tanBFG

atanba

:bAD22.53BDOPOABEDPB90ODOBOPODOBODPBDBE30PPOA1

2bAPAP18360AFHDGOABCDEFGAADAGAEDABGAEBAEBAEADOGBODGBEBOGDAO90Rt

AHEHAHABAH77

23．BFGa:2

tanGFDtana

2b2ADFDADFAFBG34OOPOADAGBAEDGBEODOBODOBOD0ABE

PAOPPOA180

2bAEFG

O360

60b41803C90ACBC11ABBBDADABD3622PCAPAQAQ3EFBCEAFMAF上NACCMNMADBC22QHCACAPQ角质得PHQHCPHAQ453EAFBAE15EACAFDDNMNMADBBDABDACBADADBC12ABD

1AD2

3622QQHHH9