ʱ : һ 辽宁省沈阳市2019-2020学年中考数学三模考试卷含解析 - 百度文库ϿʼĶ
벹ȫͳͼ
У־Ը600ˣУ꼶Լж־Ըߣ
2510֣ĸԼΪ700kmס˴ݳֱݺšA롰˺šBǰ֪AƽٶȱBƽٶ80km/hAʻʱBʻʱ40%ʻʱֱΪ٣
2612֣ͼ٣״ȫֱͬABCEFGһ𣨵AEغϣ֪AC=8cmBC=6cmC=90㣬EG=4cmEGF=90㣬OǡEFGбϵе㣮
ͼڣEFGͼٵλó1cm/sٶABƽƣڡEFGƽƵͬʱPӡEFGĶG1cm/sٶֱDZGFF˶PFʱPֹͣ˶EFGҲֹ֮ͣƽƣ˶ʱΪxsFGӳ߽ACHıOAHPΪycm2ǵPGFغϵ
1xΪֵʱOPAC
2yx֮ĺϵʽȷԱxȡֵΧ
3Ƿijһʱ̣ʹıOAHPABCıΪ1324ڣxֵ1142=129961152=132251162=134564.42=19.364.52=20.254.62=21.16 ڣ˵ɣοݣ2712֣ͼھABCDУԽACBDཻڵO
1AOBƽƺΣƽƺķΪADķƽƵľΪADij 2۲ƽƺͼΣ˾ABCD⣬һƽıΣ֤Ľۣ
ο
һѡ⣨12С⣬ÿС4֣48֣ÿСĸѡУֻһǷĿҪģ 1B ⡿
⣺Aa2+a2=2a2A Ca2a3=a5C Da8a2=a6D ѡB.
㣺ͬͬ͡ݵij˷ͬݵijij˷ 2B
BF۵֪AEֱƽBFݹɶAE=5ֱֱʾBH=
122418 ֤BFC=90㣬ɵBF=ùɶCF=
555⡿
BF۵֪AEֱƽBF
BC=6EΪBCе㣬 BE=3 ֡AB=4 AE=
AB2?BE2?42?32=5
11AB?BE?AE?BH 2211?3?4??5?BH 221224BH=BF=
55FE=BE=EC BFC=90㣬 CF=BC2?BF2?ѡB 㾦
Ƿ۱任ʡεʼɶӦã۵һֶԳƱ任Գƣ۵ǰͼε״ʹС䣬λñ仯ӦߺͶӦǽĹؼ 3D
ֱùֱһֱߵĴԼ߶δֱƽߵֱһֱߵĴߡƽߵֱóĴ𰸣
⡿ֱһֱߵĴߣ۲֪ͼڷϣ
߶εĴֱƽߣ۲֪ͼ۷ϣ
ֱһֱߵĴߣ۲֪ͼܷϣ ǵƽߣ۲֪ͼٷϣ
ȷǣ٩ک۩ܩ ѡD
㾦Ҫ˻ͼȷջͼǽؼ 4D
εʿɵAB=BC=ADABC=BAD=90㣬ٸе㶨AE=BFȻá߽DZߡ֤ABF͡DAEȫȣȫζӦȿɵáBAF=ADEȻ
ADE+DAF=BAD=90㣬ӶAMD=90㣬ٸڲǵĶɵáAME=90㣬ӶжϢȷߵĶжϳADE١EDBȻBAF١EDBжϳڴֱεжϳAEDMADMEAƣζӦ߳ɱɵ
62?(24218)=
55AMMDAD???2ȻMD=2AM=4EMжϳȷABCDı߳Ϊ2aEMAMAEùɶʽAFٸζӦ߳ɱAMȻMFaɵõAM=
2MFжϳȷMMNABNMNNBȻùɶʽBM3MGHABOOKGHKȻOKMKùɶʽMOεBOȻùɶ涨жϳBMO=90㣬Ӷжϳȷ ⡿
ABCDУAB=BC=ADABC=BAD=90㣬 EFֱΪABBCе㣬 AE=BF=
1BC 2ڡABF͡DAEУ
?AEBF???ABC?BAD ?ABAD?ABFաDAESAS BAF=ADE
ߡBAF+DAF=BAD=90㣬 ADE+DAF=BAD=90㣬
AMD=180-ADE+DAF=180-90=90㣬 AME=180-AMD=180-90=90㣬ʢȷ DEǡABDߣ ADE١EDB
BAF١EDBʢڴ ߡBAD=90㣬AMDE AEDסMADסMEA
AMMDAD???2 EMAMAEAM=2EMMD=2AM MD=2AM=4EMʢȷ
ABCDı߳Ϊ2aBF=a RtABFУAF=AB2?BF2??2a?2?a2?5a
ߡBAF=MAEABC=AME=90㣬 AMEסABF
AMAE? ABAF
AMa? 2a5aAM=
25a 525a35a =55MF=AF-AM=5a?