Cho tam giac ABC co AB=24cm,AC=30cm,BC=36cm.Cac duong trung tuyen AM va BN cat nhau tai G.Goi O la giao diem cua cac duong phan giac AD va BE.Tinh AE,EC,BD,DC,OG?
cho tam giac ABC vuong tai A duong cao AH
a) chung minh 2 tam giac HBA va HAC dong dang voi nhau
b) chung minh AH.BC=AB.AC
c) cho biet AB=12cm AC=16cm tinh o dai AH va dien tich tam giac ABC
d) gia su 1 duong thang a song song voi canh AC cat canh AB BC theo thu tu tai M va N xac dinh vi tri cua diem M de tu giac AMNC bang tam lan dien tich tam giac BMN
cho tam giac abc vuong tai a,duong cao ah phan giac ba cat nhau tai e biet ab=6cm,ac=8cm
a) chung minh AB.CD=AE.BC
b) chung minh AD,AE
Cho tam giac ABC. Mot duong thang song song voi BC cat cac canh AB, AC theo thu tu o D va E. Goi G la mot diem thuoc canh BC. Tinh dien tich tu giac ADGE biet dien tich tam giac ABC bang 16cm, dien tich tam giac ADE bang 9 cm
Cho hinh chu nhat ABCD biet AB=8,AD=6 duong cheo AC,BD cat nhau tai O ,Qua D ke duong thang d vuong goc voi BD ,d cat tia BC o E.
a)CM tam giac BDE dong dang voi tam giac BCE
cho hbh ABCD AB>BC lay diem M tuy y tren AB, M#A M#B DM cat AC tai K ,cat BC tai N
a) tam giac NMB dong dang voi tam giac NDC
tam giac AKD dong dang voi tam giac CKN
b) KB.KB=KM.KN
c) biet NB=6cm,NC=15 cm,MB=4cm. Tim ti so dong dang cua tam giac NMB va tam giac NDC . Tinh dien tich hinh binh hanh ABCD
cho tam giac ABC vuong tai A ke duong thang d song song voi BC , BH vuong goc voi d tai H
a) chung minh \(\Delta ABC\) dong dang voi \(\Delta ABH\)
b) ve hinh chieu cua C xuong d tai K , cm : AH.AK=BH.BK minh k nho lam....
c) BH giao AB tai M . Tinh AH va dien tich tam giac MBC neu AB=3 AC=4 BC=5
cho tam giac ABC vuong tai,duong cao AH,biet HB=25cm,HC=36cm,AH=30cm.
a/ chung minh tam giac HBA dong dang voi tam giac HAC.
b/tinh do dai cac doan thang AB,BC,AC
Cho tam giác nhọn ABC, các đường cao BD,CE cắt nhau ở H. Chứng minh rằng : a, Tam giác ABC va tam giac ACE b, CM : HC . HE = HB . HD c, Cho AB = 5cm, BC = 6cm, S tam giac ABC = 12 cm^2. Tinh S tam giac ADE
