cho tam giác DEF vuông tai D EM la tia phan giac cung tai D,Ea DEF) tu M ke MI vuong goc voi EF( I thuoc EF) MI cat DI tai K a. cho DE =6cm EF=10cm tinh DF b. chung minh tam giac DEM=tam giac IEN c.chung minh tam giac FKE d.chung minh DEF=2MF
1/Cho tam giac ABC co goc A=120 do.Cac tia phan giac BE, CF cua ABC va ACB cat nhau tai I (E,F lan luot thuoc cac canh AC,AB).Tren canh BC lay 2 diem M,N sao cho BIM=CIN=30 do.
a)Tinh so do cua goc MIN
b)Chung minh CE+BF<BC
2/Cho tam giac DEF vuong tai D va DF>DE, ke DH vuong goc voi EF (H thuoc EF). Goi M la trung diem cua EF.
a)Chung minh goc MDH=goc E-goc F
b)Chung minh EF-DE>DF-DH
cho tam giac def vuong tai d cho e la tia phan giac ke km vuong goc ef keo dai km cat duong thang de tai i chung minh dk=km;de=em
cho tam giac ABC vuong tai A. Ke AH vuong goc voiBC, H thuoc BC. Tia phan giac cua goc HAC cat BC . Chung minh
a, tam giac ABD la tam giac can o A
b,Tu D ke DK vuong goc voi AC / K thuoc AC/ Chung minh
A la phan giac cua HDC
CHO TAM GIAC ABC CO AD LA PHAN GIAC CUA GOC A (D THUOC BC). KE DEVUONG GOC VOI AB, KE DF VUONG GOC VOI AC
a, CHUNG MINH TAM GIAC AED= TAM GIAC AFD
b, TIA FD CAT TIA AB TAI P, TIA ED CAT TIA AC TAI Q. CHUNG MINH AP=AQ
c, TIA AD CAT PQ TAI M. CHUNG MINH AM LA DUONG TRUNG TRUC CUA DOAN THANG PQ
d, CHO GOC BAC=50 DO. TINH SO DO GOC APQ VA GOC AQP
Cho tam giac can DEF ( DE=DF ). Goi N va M lan luot la trung diem cua DE va DF, ke DH vuong goc voi EF tai H.
1) Chung minh: HE=HF. Gia su DE=DF=5cm; EF=8cm. Tinh do dai doan DH
2) Chung minh: EM=FN va \(\widehat{DEM}=\widehat{DFN}\)
3) Chung minh 3 diem D, K, H thang hang
MINH CAN GAP CAC BAN GIUP MINH NHE
a)Tinh ti so AG/AD b)Chung minh tam giac ABD=tam giac ACD c)Chung minh DE=DF dChoAC=10cm,BC=12cm,tinh AG
Cho tam giac ABC(AB khac AC) Duong trung tuuc cua doan BC tai H cat tia phan giac Ax cua Goc A tai K. Ke KE,KF theo thu tu vuong goc voi AB va Ac
a, Cm BE=CF
b, Noi EF cat BC tai M. CHUng minh M la trung diem cua BC
Cho tam giac DEF co DE=DF=12cm;gocDEF=55
Tam giac DEF la tam giac gi,vi sao
tinh so do goc EDF
ke duong cao DI(Ithuoc EF).tinh DI
Goi Gla trong tam cua tam giac DEF tinh khoang cach tu trong tap den dinh DCua tam giac DEF