最新七年级下册数学几何复习题1优秀名师资料.docx
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最新七年级下册数学几何复习题1优秀名师资料
七年级下册数学几何复习题_1
12（如图所示，在?
ABC中，?
A,80?
，?
B,30?
，CD平分?
ACB，DE?
AC.
（1）求?
DEB的度数;
（2）求?
EDC的度数（
解
（1）在?
ABC中，?
A,80?
，?
B,30?
，
?
?
ACB,180?
?
A,?
B,70?
.
?
DE?
AC，
?
?
DEB,?
ACB,70?
.
（2）?
CD平分?
ACB，
1?
?
DCE,?
ACB,35?
.2
?
?
DEB,?
DCE，?
EDC，
?
?
EDC,70?
35?
35?
.
13（已知，如图，?
1,?
2，CF?
AB于F，DE?
AB于E，求证:
FG?
BC.（请将证明补充
完整）
证明?
CF?
AB，DE?
AB（已知），
?
ED?
FC（）（
?
?
1,?
BCF（）（
又?
?
1,?
2（已知），
?
?
2,?
BCF（等量代换），
?
FG?
BC（）（
解在同一平面内，垂直于同一直线的两条直线互相平行;两直线平行，同位角相
等;内错角相等，两直线平行（
14（如图，已知三角形ABC，求证:
?
A，?
B，?
C,180?
.
分析:
通过画平行线，将?
A、?
B、?
C作等角代换，使各角之和恰为一平角，依辅助
线不同而得多种证法，如下:
证法1:
如图甲，延长BC到D，过C画CE?
BA.
?
BA?
CE（作图所知），
urbanarea2.5.2YibincityinYibincity,accordingtoresourceandenvironmentcharacteristicsUrbanpopulationandurbanspatialdistribution,spatialdistributionofindustries,majorinfrastructureCorridorlayout,combinedwiththefuturedevelopmenttrendofsyntheticjudgments,planning,urbanspatialstructureofurbansystemcanbesummarizedas:
"apolealongthetwoaxes"."A"referstothemetropolitanareaalongtheYangtzeRiver,isthecoreareaofthedevelopmentofthecity.PlanstobuildfortheYangtzeRivereconomicbeltonthepillar,advancingalongthe...GuangheRiver,Yiliang,prestigeoftheexternalcohesionofzhaotong,Yunnan,internalconnectingYibincitytotheNorth.TheSichuan-Yunnan-GuizhouborderareaofYibin,inthecityofzhaotong,liupanshuithree,zhaotongcity,themostpopulousandmostextensiveregions,themosteconomicallybackward,totheNorthinWumengmountainareaofyanjin,shuifu,suijiangcountiesradiationpowerisrelativelyweak.Yibincityandinfrastructureinsuchareasshouldbestrengthenedanddocking,extendingsouthwardtopublicservices,promotethedevelopmentofmineralresourcesinNortheastYunnan,expandoureconomichinterland,drivingsynchronousliftinginSichuan-Yunnan-Guizhouborderarea.Thisurbanaxiswithmineralresourceadvantages,focusonthedevelopmentofadvancedtechnology,comprehensiveutilizationofresourcesofhigherenergy,newbuildingmaterials,chemicalindustry,developingnewenergyandminingtowns.Urbanspaceorganization-ingongxianCounty,Gao,junlianCountyCenterforareaorganizations,improve,Gao,Gong,junlianCountycomprehensiveservices,andpromotingregionaleconomicdevelopmentandpopulationgrowthoftheagglomeration.Alongthemaintrafficarteriestoimplement"point-axisdevelopment"modekeyrepeatedly,Shahetown,XiaoZhen,LuotableZhen,Luotown,loveMuZhenandothertownsasdistrictdevelopmentfocusesoncitiesandtowns,promotethedevelopmentofdistrict
?
?
B,?
1，?
A,?
2（两直线平行，同位角、内错角相等）（
又?
?
BCD,?
BCA，?
2，?
1,180?
（平角的定义），
?
?
A，?
B，?
ACB,180?
（等量代换）（
如图乙，过BC上任一点F，画FH?
AC，FG?
AB，这种添加辅助线的方法能证明?
A，?
B，?
C,180?
吗,请你试一试（
解?
FH?
AC，
?
?
BHF,?
A，?
1,?
C.
?
FG?
AB，
?
?
BHF,?
2，?
3,?
B，
?
?
2,?
A.
?
?
BFC,180?
，
?
?
1，?
2，?
3,180?
，
?
，?
，?
180?
.即ABC
15（（2010?
玉溪）平面内的两条直线有相交和平行两种位置关系（
（1）如图a，若AB?
CD，点P在AB、CD外部，则有?
B,?
BOD.又因?
BOD是?
POD的外角，故?
BOD,?
BPD，?
D，得?
BPD,?
B,?
D.将点P移到AB、CD内部，如图b，以上结论是否成立,若成立，说明理由;若不成立，则?
BPD、?
B、?
D之间有何数量关系,请证明你的结论;
（2）在图b中，将直线AB绕点B逆时针方向旋转一定角度交直线CD于点Q，如图c，则?
BPD、?
B、?
D、?
BQD之间有何数量关系,（不需证明）（3）根据
（2）的结论求图d中?
A，?
B，?
C，?
D，?
E，?
F的度数（
解
（1）不成立，结论是?
BPD,?
B，?
D.
延长BP交CD于点E，
isrelativelyweak.Yibincityandinfrastructureinsuchareasshouldbestrengthenedanddocking,extendingsouthwardtopupowerregions,themosteconomicallybackward,totheNorthinWumengmountainareaofyanjin,shuifu,suijiangcountiesradiationGuizhouborderareaofYibin,inthecityofzhaotong,liupanshuithree,zhaotongcity,themostpopulousandmostextensive-Yunnan-er,Yiliang,prestigeoftheexternalcohesionofzhaotong,Yunnan,internalconnectingYibincitytotheNorth.TheSichuanevelopmentofthecity.PlanstobuildfortheYangtzeRivereconomicbeltonthepillar,advancingalongthe...GuangheRivthedsummarizedas:
"apolealongthetwoaxes"."A"referstothemetropolitanareaalongtheYangtzeRiver,isthecoreareaof,combinedwiththefuturedevelopmenttrendofsyntheticjudgments,planning,urbanspatialstructureofurbansystemcanbepatialdistribution,spatialdistributionofindustries,majorinfrastructureCorridorlayouturbanarea2.5.2YibincityinYibincity,accordingtoresourceandenvironmentcharacteristicsUrbanpopulationandurbans2velopmentofdistrictictdevelopmentfocusesoncitiesandtowns,promotethedeaxisdevelopment"modekeyrepeatedly,Shahetown,XiaoZhen,LuotableZhen,Luotown,loveMuZhenandothertownsasdistr-theagglomeration.Alongthemaintrafficarteriestoimplement"pointces,andpromotingregionaleconomicdevelopmentandpopulationgrowthofingongxianCounty,Gao,junlianCountyCenterforareaorganizations,improve,Gao,Gong,junlianCountycomprehensiveservi-ingnewenergyandminingtowns.Urbanspaceorganizationehensiveutilizationofresourcesofhigherenergy,newbuildingmaterials,chemicalindustry,developGuizhouborderarea.Thisurbanaxiswithmineralresourceadvantages,focusonthedevelopmentofadvancedtechnology,compr-Yunnan-usliftinginSichuanhronoblicservices,promotethedevelopmentofmineralresourcesinNortheastYunnan,expandoureconomichinterland,drivingsync
?
AB?
CD，?
?
B,?
BED.
又?
BPD,?
BED，?
D，
?
?
BPD,?
B，?
D.
（2）结论:
?
BPD,?
BQD，?
B，?
D.
（3）设AC与BF交于点G.
由
（2）的结论得:
?
AGB,?
A，?
B，?
E.
又?
?
AGB,?
CGF，?
CGF，?
C，?
D，?
F,360?
，?
?
A，?
B，?
C，?
D，?
E，?
F,360?
.A
D14（把一副常用的三角板如图所示拼在一起，那么图中?
ADE是度（
ECB
第14题
2（如图，在?
ABC和?
ABD中，现给出如下三个论断:
?
AD,BC;?
?
C,?
D;?
?
1,?
2。
请选择其中两个论断为条件，一个论断为结论，另外构造一个命题（
?
,?
（1）写出所有的正确命题（写成“”形式，用序号表示）:
（,?
（2）请选择一个正确的命题加以说明（你选择的正确命题是:
,
说明:
3（如图，直线AD和BC相交于O，AB?
CD，?
AOC,95?
，?
B,50?
，求?
A和?
D.
4（如图，?
ABC中，角平分线AD、BE、CF相交于点H，过H点作HG?
AB，垂足为G，那么?
AHE,?
CHG吗,为什么,
ingongxianCounty,Gao,junlianCountyCenterforareaorganizations,improve,Gao,Gong,junlianCountycomprehensiveservi-ewenergyandminingtowns.Urbanspaceorganizationehensiveutilizationofresourcesofhigherenergy,newbuildingmaterials,chemicalindustry,developingnGuizhouborderarea.Thisurbanaxiswithmineralresourceadvantages,focusonthedevelopmentofadvancedtechnology,compr-Yunnan-ftinginSichuanusliservices,promotethedevelopmentofmineralresourcesinNortheastYunnan,expandoureconomichinterland,drivingsynchronoelativelyweak.Yibincityandinfrastructureinsuchareasshouldbestrengthenedanddocking,extendingsouthwardtopublicrisrons,themosteconomicallybackward,totheNorthinWumengmountainareaofyanjin,shuifu,suijiangcountiesradiationpowehouborderareaofYibin,inthecityofzhaotong,liupanshuithree,zhaotongcity,themostpopulousandmostextensiveregiGuiz-Yunnan-iliang,prestigeoftheexternalcohesionofzhaotong,Yunnan,internalconnectingYibincitytotheNorth.TheSichuanpmentofthecity.PlanstobuildfortheYangtzeRivereconomicbeltonthepillar,advancingalongthe...GuangheRiver,Ydeveloarizedas:
"apolealongthetwoaxes"."A"referstothemetropolitanareaalongtheYangtzeRiver,isthecoreareaofthebinedwiththefuturedevelopmenttrendofsyntheticjudgments,planning,urbanspatialstructureofurbansystemcanbesummpatialdistribution,spatialdistributionofindustries,majorinfrastructureCorridorlayout,comurbanarea2.5.2YibincityinYibincity,accordingtoresourceandenvironmentcharacteristicsUrbanpopulationandurbans3mentofdistrictictdevelopmentfocusesoncitiesandtowns,promotethedevelopaxisdevelopment"modekeyrepeatedly,Shahetown,XiaoZhen,LuotableZhen,Luotown,loveMuZhenandothertownsasdistr-agglomeration.Alongthemaintrafficarteriestoimplement"pointces,andpromotingregionaleconomicdevelopmentandpopulationgrowthofthe
5（如图17，在?
ABC中，AD为?
BAC的平分线，DE?
AB于E，DF?
AC于F，?
ABC面积
2是，AB=20厘米，AC=8厘米，求DE的长（28cm
第5题
6（如图，已知AB?
CD，垂足为B，AB=DB，AC=DE（请你判断?
D与?
A的关系，并说明理
由（
A
E
CBD
第6题
7（如图，AD=BC，DC=AB，AE=CF，找出图中的一对全等三角形，并说明你的理由（
DCF
E
BA
第7题
8（如图，已知M在AB上，BC=BD，MC=MD（请说明:
AC=AD（
C
MBA
第8题D
usliftinginSichuanhronoblicservices,promotethedevelopmentofmineralresourcesinNortheastYunnan,expandoureconomichinterland,drivingsyncisrelativelyweak.Yibincityandinfrastructureinsuchareasshouldbestrengthenedanddocking,extendingsouthwardtopupowerregions,themosteconomicallybackward,totheNorthinWumengmountainareaofyanjin,shuifu,suijiangcountiesradiationGuizhouborderareaofYibin,inthecityofzhaotong,liupanshuithree,zhaotongcity,themostpopulousandmostextensive-Yunnan-er,Yiliang,prestigeoftheexternalcohesionofzhaotong,Yunnan,internalconnectingYibincitytotheNorth.TheSichuanevelopmentofthecity.PlanstobuildfortheYangtzeRivereconomicbeltonthepillar,advancingalongthe...GuangheRivthedsummarizedas:
"apolealongthetwoaxes"."A"referstothemetropolitanareaalongtheYangtzeRiver,isthecoreareaof,combinedwiththefuturedevelopmenttrendofsyntheticjudgments,planning,urbanspatialstructureofurbansystemcanbepatialdistribution,spatialdistributionofindustries,majorinfrastructureCorridorlayouturbanarea2.5.2YibincityinYibincity,accordingtoresourceandenvironmentcharacteristicsUrbanpopulationandurbans4velopmentofdistrictictdevelopmentfocusesoncitiesandtowns,promotethedeaxisdevelopment"modekeyrepeatedly,Shahetown,XiaoZhen,LuotableZhen,Luotown,loveMuZhenandothertownsasdistr-theagglomeration.Alongthemaintrafficarteriestoimplement"pointces,andpromotingregionaleconomicdevelopmentandpopulationgrowthofingongxianCounty,Gao,junlianCountyCenterforareaorganizations,improve,Gao,Gong,junlianCountycomprehensiveservi-ingnewenergyandminingtowns.Urbanspaceorganizationehensiveutilizationofresourcesofhigherenergy,newbuildingmateria
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