中考数学突破-选择填空压轴题

中考学突破----选择填空压题一、择题1．ABCDADBC=CDAD=

CDAE=2

AEAFBFA1

B

CD2考点专题分析BCCE=DAE=G”ADECG=AD=AFGFAMMDDNBMCNCNMFBF=BMMF解答CE=DEADBCDAEADEGCEADEGCE=AD

AE=EG=2

=+AEAF

=4

-1-

=GF=cos30°=4

×÷

AMDDNBCAD=

ABCDBMCNוMG

=6

=6

AMBCFAMGFMAF=MF=62D

2=4

点评2．lllABC3sinA

B

C

D-2-

考点专题分析AlBBElE=BCE”ACDCBECDBEAC

解答AADlBBElEl，ll113ACD=90°+ACD=90°ABC=BCCBE=BEeq\o\ac(△,Rt)ACDACABC=sin=

==

×

==

D点评3．=30°AAA…B…OM1ABB…OAeq\o\ac(△,A)eq\o\ac(△,)A2346-3-

A6

B

C32

D考点专题分析AABBB3233B=8BB…1512解答eq\o\ac(△,A)eq\o\ac(△,)B=B12=60°12=120°MON=30°1=180°30°=30°3=60°5=180°30°=90°MON=1=30°OAB1=1eq\o\ac(△,A)eq\o\ac(△,)Beq\o\ac(△,A)eq\o\ac(△,)BA344=12=60°ABABB2311=7=30°=2B=2B33=4B=8B1BB=162-4-

=32A1C点评此AB141BB24．ABCDEFOEFADA

B15D考点相专题压分析连OAOBOA=ODA解答解OAODABCOBCBCDOEFEDO=30°=30°OD=OB

DOE+EOA=+DOA=EOBDOAOD=OBADBEA

-5-

点评本5aay=010Ay=

B=

Cy

D=考点专题压分析根P3aa解答

π×4=40aaa03a=

=Aπ

π=±2662=-6-

=D

点评6ABCDADBCBCDADC=120°10A

B

C

D

考点专题分析解答

=

ADBCADC==30°

=

BAC=90°B=60°BC=2ABCD=AB+BC+CD+=BC×3+BC=4cm=×4=2cm-7-

=[π×2×B

π

点评7．eq\o\ac(△,Rt)ABCCBC=4ACA20B32π16Dπ考点分析解答SSS23+++++SABCS++S+423424=×16+πC点评8．6O沿AB

DCDOD-8-

A

B

C6

D考点分析COAB解答COCEAB=6CDOD=4ODOB=6DE=OCCD=×8=4=DE=4eq\o\ac(△,Rt)OEBOEBE=

=ABB

点评9eq\o\ac(△,Rt)ABCC=90°AC=8Dtan=-9-

A

B

C

D考点三专题压分析设OACFGOEOFOGABAF=CGOFCGOF=CF=OF=x=AE=6==8xAEDE解答解OOEABOFOGOGC=OFCOED=90°=90°AB=10ABC=CG=90°OFCGOGOFOFCG==xxBE=BG+8x=10OFAEDADDE=1-10-

ODA=D

点评此10．BCADBC==5PPDAPDA

B

C

D考点轴专题压分析要解答解DBCEADBCBE=AD=2BC==5EC=3AB=DE=4ABAAB=ABADPDP在ADPA+PDAABPAD-11-

BPeq\o\ac(△,)BP=AD=1APAPD

=

=2×4÷C

=

点评此11ABCAB=BACDADADADDE=

CDA1

B

C

D考点正分析根ADEF是=90°ABDCFBDAD解答解AAMBDM-12-

BAC=90°AB=AC=4B=ACBBC=8=2BD2=6BAC=90°AB=ACAMB=BAM=45°BMABBMAM=44=2eq\o\ac(△,Rt)=ADEF==AF==90°AD=AFDAF=90°BAC=90°BAD=90°DA=xACF

ABDSASCF==ACB=45°DPCDPC

=

=

-13-

x+3x=，=1A点评本x12．4DCEQADDQA2

B

C2D4考点专题分析DAE于DDPADDDAEDPDQ+解答DDDPDDAFD=AFD=AF=CAEeq\o\ac(△,D)eq\o\ac(△,)，-14-

2222DAE′=AD=4DP+ABCDDADAPPDeq\o\ac(△,Rt)DD+AP=AD=16APPD2PD

=AD

2D

=16DC

DQ+

点评13．ly

xxAlyll2AMNBAMNBA3B8D考点分析lMxAMN-15-

四NBAM形四NBAM形NBAM解答l=x+2=x1yx=0A0llAMBNMAyN1NCABAMBNMNABNBAMNBAM1=2ABNC=MN+NCA点评B14．=ax++cab+b2ax+bx+32+-16-

A4

B

C2

D考点二专题数分析

0a+b+c

=12b+=03b=2a++=a2b+=a4a3=0解答解10++x

=1030c=031aab++c3a2bc=4a3=702bcaC点评本ax+bxcaa0=0c-17-

15．

ABMlxllCAMCNA32

B

C50

D考点分析lBC解答yx6xy=x1x4lAM4AB1=4=AC=+BCS+=×8×4=32AMCNACMA点评二、空题-18-

．5485考点规专题压分析由517×3+2=5353×3+2=161161×3+2=485解答解55×3+2=1717×3+2=5353×3+2=1611485点评此2．12691考点规专题压分析观1+4=51+4+9=14-19-

考点解答解1+4=51+4+9=14…+1+11+4+9+16+25+36=91点评本3eq\o\ac(△,Rt)C=90°ABABDE

BC-20-

222专题分析OOFBCAAMOF=AMOA=AM=OFOM=AMCF=COFCFMFOMCF+解答解法一OOFAMOF=90°=BOFAOMOAM=90°BOFAOMBOFAASAM=OMFBACB=AMF=CFM=90°ACFMAMCF=MFOF==6

CFOFOCCF==OMOFFM5=1=+BF-21-

7解法OOMCAMONOMAONBOM=NOACB=6

=ONMACMACBC=CN+NB=6+1=77点评-22-

224ABCyC20B0tanA考点一专题压分析根=CBOB=OBC=45°ABC=90°ABCBC=2

AAB解答解==OCABCBC=2ACAxx1

=x+=2

eq\o\ac(△,Rt)+AC=ABtanA=

==点评本-23-

5．b1323+21=6m3考点解专题压分析根2bm解答解ma+b1=2m2m1=23=0m+1=0m=331点评根2b06．ABCDABAD=BCABA=考点概专题压分析本解答解=点评用-24-

7lyxAlBlyAAyl1l…24

考点一专题规分析根lxA2A解答

ly=lx30°AB=30°=1=2AB=Bl=40A016…4

x-25-

4点评本x…238eq\o\ac(△,Rt)OAB上PA考点轴分析作DOBAPDDNOAPAAMADCD解答解ADCD交PAPDDN+DP=PA+=PD+=B62AB

OA=60°

=××AMAM-26-

AD=2×3=6AMB=90°=60°BAM=30°=90°DN=30°AN=AD=3DNC10=63=2

eq\o\ac(△,Rt)DNCDC=+

=

点评本30P9BCBC=4BC=690°4-27-

考点直专题计分析如解答解EFADDGBCCD以DEDADBCDE=DCDEDCCDG=DGBCAD=BG==BCAD=6ADE•EF×4×2=44点评本10．=x4≤4Cx1CA180°C12CA180°CA23…m=3-28-

考点二专题规分析求CP解答解x4≤40C180°A12180°A233…C360xy=x4010xy×37=3点评本C11APPPPy1

x01xPPABPy323

0AxP

-29-

考点反专题综分析

PCyCDxDEEPFDaCP=a=331eq\o\ac(△,Rt)Peq\o\ac(△,Rt)eq\o\ac(△,Rt)ADOBPC=AD=a=PDaP111112=aPP2beq\o\ac(△,Rt)Peq\o\ac(△,Rt)EEP==OD+DE=2+=b2333b解答解PCyDDPxEFPD22Pa=aOC=1AP1Peq\o\ac(△,Rt)BAOeq\o\ac(△,Rt)APD2OBD=11OAD=a12OD+aaPy=x02PP32Peq\o\ac(△,Rt)P3

=a=1-30-

考点E=PFDE=3=ODDE2+=bb=1==

+1

点评本．BBtanOBC=

-31-

专题分析OBCA==60°EODDE=xOEOD=BEOD解答ODBCAOBCA=B=60°OED=60°EOD=30°eq\o\ac(△,Rt)ODEDE=2xODODBCD==BC=9AE=7+2x

xODOBC=

=

点评13．ADGBEDGHDGHAB=BH

-32-

考点旋分析连交ADDEA与EGADAE=

ANGNDN1=3DG

=

S=GE=DGHEHEBH=BE解答解GEADNDE与EGADAE=

AN==1=41=3eq\o\ac(△,Rt)DNGDG=

90°DG=

=•=DGHEDEGHE=

BH=HE

+

=

-33-

点评本．ABCDBEDEA