tam giac ABC co B>c, phan giac goc ngoai cua A cat bc tai e. A=60,AEB=15 goc abc =
Cho tam giac ABC co goc B>goc C duong thang chua tia phan giac goc ngoai dinh A cat duong thang BC o E.CM goc AEB=1/2.(goc B-goc C)
Cac ban co gang giup do. Neu co ai muon thay hinh anh cua minh thi len facbook nhan Le Dinh LUC
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
cho tam giac ABC co B=110 do C =50 do phan giac goc ngoai tai dinh A cat tia doi cua tia BC tai D tinh cac goc cua tam giac ABD
Cho tam giac ABC co goc A khac goc B cac tia phan giac trong va ngoai cua goc C lan luot cat duong thang BA tai D va E tinh goc CED theo goc A va goc B cua tam giac ABC
Cho tam giac ABC .Cac duong thang chua tia phan giac cua cac goc ngoai dinh B va o dinh C cat nhau tai K.Tinh goc a biet goc BCK =50°
1.cho tam giac ABC co goc B-C=alpha phan giac AD
a) tinh gocADC,ADB theo alpha
b)Ve duong cao AH tinh goc HAD
2.chotam giac ABC,gocA =alpha,cac tia ohan giac cua B va C cat nhay tai I.Phan giac cat goc ngoai tai dinh B,C cat nhau tai K.Tia p/g goc B cat goc ngoai o dinh C.tinh cac goc BIC,BKC,BEC theo alpha.
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