cho tam giac MNP vuong tai M, co MN=18cm,MP=24cm.
a/ tinh NP.
b/ duong trung tuyen MK va duong trung tuyen NE cat nhau tai G. tinh MG
c/ tren tia doi cua tia NE, lay diem F sao cho EN=EF.chung minh:FP vuong goc MP
Cho tam giac ABC vuong tai A co AB=3cm,AC=4cm.Goi AM la duong trung tuyen cua tam giac ABC tren tia doi cua tia AM lay diem D sao cho AM=MD
a)Tinh BC
b)C/m AB // CD
c)C/m goc BAM > goc CAM
d)Goi H la trung diem AM,tren duong thang AH lay E sao cho AH=HE , CE cat AD tai F . C/m F la trung diem CE
Cho tam giac ABC vuong tai A co AB=3cm,AC=4cm.Goi AM la duong trung tuyen cua tam giac ABC tren tia doi cua tia AM lay diem D sao cho AM=MD
a)Tinh BC
b)C/m AB // CD
c)C/m goc BAM > goc CAM
d)Goi H la trung diem AM,tren duong thang AH lay E sao cho AH=HE , CE cat AD tai F . C/m F la trung diem CE
cho tam giac ABC co 3 duong trung tuyen AI,BE,CF cat nhau tai G.Tren tia doi cua tia IA lay M sao cho IM=IG Tren tia doi cua tia EB lay N sao cho EN=EG.TRen tia doi cua tia FC lay P sao cho PF=FG
CMR:
a) tam giac MNP=tam giac ABC
b)G la trong tam cua tam giac MNP
cac ban giup minh nhe minh tick cho .Cam on
tam giac abc co hai duong trung tuyen bm va cn .tren tia doi cua tia mb lay diem d sao cho md =mb .tren tia doi cua tia cn lay diem e sao cho ne=nc.cminh d ,a ,e thang hang
CHO TAM GAIC ABC VUONG TAI A, CO AB = 3CM, AC=4CM.GOI AM LA DUONG TRUNG TUYEN, TREN TIA DOI CUA TIA MA LAY DIEM D SAO CHO AM=MD
A) TINH DO DAI CANH BC
B) CHUNG MINH AB=CD, AB//CD
C) CHUNG MINH GOC BAM>GOC CAM
D) GOI H LA TRUNG DIEM CUA BM, TREN DUONG THANG AH LAY DIEM E SAO CHO AH=HE, CE CAT AD TAI F. CHUNG MINH F LA TRUNG DIEM CUA CE
a/ Áp dụng định lí Pytago vào tam giác vuông ABC ta được:
BC^2=AB^2+AC^2=3^2+4^2=5^2
=> BC=5 cm
b)c/m tam giác BAM= tam giác CDM=><ABC=<DCB mà 2 góc này là 2 góc so le trong=>AB//DC
VÌ tam giác BAM= tam giác CDM=> AB=CD
cho tam giac abc vuong tai a duong cao ah trung tuyen am.tren tia doi tia ma layd sao cho dm=ma .tren tia doi cua tia cd lay diem i sao cho ci=ca,qua i ke duong thang song song voi ac cat ah tai e
cm:AE=BC
Cho tam giac ABC can tai A co AD la duong trung tuyen
a)Chung minh tam giac ABD= tam gaic ACD va AD vuong goc voi BC
b)Cho AB=10cm,BC=16cm. Tinh do dai AD va so sanh cac goc cua tam giac ABC.
c) Ve duong trung tuyen CF cua tam giac ABC cat AD tai M. Tinh do dai AM.
d) Ve DH vuong goc AC tai H, tren canh AC va canh DC lan luot lay hai diem E,K sao cho AE=AD va DK=DH. Chung minh: EK vuong goc voi BC
A,
xét \(\Delta ABD\)và \(\Delta ACD\)
CÓ \(\hept{\begin{cases}AB=AC\\chungAD\\BD=DC\end{cases}}\)
SUY RA \(\Delta ABD\)=\(\Delta ACD\) (C.C.C) (1)
=> \(\widehat{BDA}\)=\(\widehat{CDA}\)
MÀ \(\widehat{BDA}\)+\(\widehat{CDA}\)=180
=> \(\widehat{BDA}\)=\(\widehat{CDA}\)=90
B, (1) => BC=DC=1/2 BC=8
ÁP DỤNG ĐỊNH LÍ PITAGO TA CÓ
\(AB^2=AD^2+BD^2\)
=> AD^2=36
=>AD=6
tam giac abc co ab bang 12 cm ac bang 15 cm bc bang 16 cm tren ab lay m sao cho am bang 3cm tum ke duong thang song song bc cat ac tai n cat trung tuyen ai tai k a tinh mn b chung minh k la trung diem mn c tren tia mn lay p sao cho mp bang 8 cm noi pi cat ac tai q chung minh tam giac qic dong dang voi tam giac aiqn
Cho tam giac ABC .Ke trung tuyen AM Tren tia doi cua tia MA lay diem E sao cho ME=MA
a,Chung minh tam giac AMB=tam giac ECM
b,Ke AH vuong goc voi BC. Ten tia doi cua tia HA lay diem D sao cho HD=HA.Chung minh :BCla tia phan giac cua goc ABD va BD=CE
c.Hai duong thang BD va CE cat nhau tai K. Chung minh :tam giac BCK can