cho tam giac ABC vuong tai A, co AB = 5cm, BC = 13. 3duong trung tuyen AM, BN, CE cat nhau tai O
a, tinh AM, BN, CE
b, tinh dien tich tam giac BOC
Cho tam giac ABC vuong o A, co AB = 5cm,BC = 13. 3 duong trung tuyen AM,BN,CE cat nhau tai O.
a, Tinh AM, BN, CE
b, Tinh dien tich tam giac BOC
cho tam giac ABC vuong tai A,co AB=5cm,BC=13cm.Ba duong trung tuyen AM,BN,CE cat nhau tai O
a)tinh AM,BN,CE
b)tinh dien tich tam giac BOC
Cho tam giac ABC vuong tai A . Ba duong trung tuyen AD BE CF. Ba duong trung tuyen AM , BN , CE cat nhau tai O
a tinh AM , BN , CE
b Tinh dt tam giac BOC
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
Cho tam giac ABC co M la diem tren canh BC sao cho BM= 2 MC va N la diem tren canh AC sao cho CN= 3 NA. Biet AM cat BN tai O. Hay tinh dien tich tam giac ABC neu biet dien tich tam giac AOB= 20cm2
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 nhon. goi h la truc tam cua tam giac abc. biet ah=bc. tinh bac
cho tam giac abc vuong tai a co c =150 trung tuyen am. duong trung truc cua bc cat cac duong thang ab va ac tai n va p
tinh k=\(\frac{AP}{PC}\)
goi i la giao diem cua bp va nc so sanh ma va mi
ai giai dc tich 20 like
cho tam giac abc vuong tai a, co ab=3 cm ac=4 cm, duong phan giac ad. duong vuong goc voi dc cat ac tai e
a) cmr tam giac abc va tam giac dec dong dang
b) tinh do dai cac doan thang bc,bd
c) tinh do dai ad
d) tinh dien tich tam giac abc va dien tich tu giac abde