cho tam giacABC co A=70 C=50 tia phan giac cua B cat AC oE tia phan giac cua BEC no cat BC o F tinh goc AEB 'goc CEF
cho tam giac ABC co AB=AC, tia phan giac cua goc A cat canh BC tai D.Lay E tren AD.CMR
a. Tam giac AEB=tam giac AEC
b. ED la tia phan giac cua goc BEC
c. AD vuong goc voi BC
CHO tam giac ABC co goc A = 60 do .Cac tia phan giac cua B va C cat nhau tai O va cat AC ,AB lan luot tai D va E .Tia phan giac cua goc BOC cat tai BC tai F .CMR : a. OE=OD=OF . b. Tam giac DEF đêu
cho tam giac ABC co A=60 cac tia phan giac cua goc B va C cat nhau tai I,cat cac canh AC,AB lan luot tai D vaE tia phan gia cua goc BIC cat BC o F tinh goc BIC
Cho tam giac ABC, goc A =60 do. Tia phan giac cua goc Bva C cat cac canh doi dien tai D va E, BD va CE cat nhau tai O. Tia phan giac cua goc BOC cat BC tai F. Chung minh a, OD=OE=OF b, Tam giac DEF la tam giac deu.
cho tam giac ABC co A = 60o. Tia phan giac cua goc B cat AC tai D. Tia phan giac cua goc C cat AB tai E. Goi O la giao diem cua BD va CE. CMR : OD =OE
Cho tam giac ABC, goc A bang 60 dọ. Tia phan giac trong cua goc B va goc C cat cac canh doi dien tai D va E, BD va CE cat nhau o O. Tia phan giac cua goc BOC cat BC tai F. CM:
a) OD=OE=OF
b) tam giac DEF deu
Cho tam giac ABC vuong tai A tia phan giac cua goc B cat AC o E
A chung minh goc BEC > 90°
B cho biet goc C-goc B =10° tinh goc AEB vaBEC
cho tam giac ABC co goc A=a . Cac tia phan giac cua goc B va C cat nhau tai I . Cac tia phan giac cua cac goc ngoai ding B va C cat nhau tai K. Tia phan giac cua g oc B cat tia phan giac ngoai ding C tai E. Tinh so do cua BKC, B . C theo a
|x|:(1/11-5/22)+|x|:(1/15-2/3)=- |-3|
cho tam giac ABC co A =70 B=50. Cac tia phan giac cua goc A va goc B cat nhau tai diem Ova cat cac canh BC,AC theo thu tu o E,F
Tinh so do goc AOB
tren canh AB lay diem P sao cho AP=AF. Chung minh OPla tia phan giac cua AOB
c, Chung minh AF+BE=AB
hướng dẫn tự làm
theo tổng 3 góc trg tam giác lấy 180 - OBA - OAB = AOB
mà phân giac thì em lấy A : 2 = AOB
B cug vậy