lam on giup nha cho tam giac abc , cac duong han giac ad va be cat nhau tai o, biet de la phan giac goc adc. tinh goc boc

cho tam giac ABC, cac duong phan giac AD,BE cat nhau tai O.Cho biet DE la tia phan giac cua goc ADC.Tinh so do goc BOC. Cac ban lam on giup minh nha 

15 minutes for you

Cho tam giac can ABC, AB=AC, cac phan giac AD;BE cat nhau tai I . M la trung diem cua EC. Chung minh :

a . \(\Delta\)IBC can

b DM//BE

c. Biet \(AD=\frac{1}{2}BE\) tinh cac goc cua tam giac ABC

Cho tam viac abc can tai a biet goc a=108 ke cac duong phan giac ad va be chung minh ad=1/2bc

Cho tam vice ABC can tai A duong cao AH phan giac BC .Tinh cac goc cua tam giac ABC biet BD =2AH

Cho tam giac ABC.Cac duong phan giac AD va BE cat nhau tai O. Biet DE la tia phan giac cua goc ADC. Tinh so do goc BOC.

cho tam giac ABC co 3 goc nhon cac duong cao AD BE CF cua tam giac ABC cat nhau tai H 

a) CM: tu giac CFHD noi tiep trong 1 duong tron xac dinh vi tri tam O cua duong tron ngoai tiep tu giac CEHD

b) CM: goc FEH bang goc DEH . CM: H la tam duong tron noi tiep tam giac DEF 

c) CM; CH = 4cm tinh do dai duong tron tam (o) va duong kinh hinh tron (o)

cho tam giac ABC co goc C nho nhat. Tu B ve 1 duong thang song song voi phan giac AD cua goc BAC, duong nay cat AC tai E .

a) Chung minh goc BAC la goc nhon

b) Chung minh tam giac ABE co 2 goc bang nhau

c)Goi M la trung diem BE. Chung minh tam giac AMB=tam giac AME va AM vuong goc voi BE

d)Ke BH vuong goc voi AC, O la giao diem cua AD voi BH biet goc A=2 goc B. Tinh goc HOD

cho tam giac ABC nhon (AB<AC)

cac duong cao AD ,BE,CF cat nhau tai  

a, cm HE.HB =HF.HC

b.CM TAM GIACEHF~tam giac CHB 

c. cm EH la phan giac DEF

d, BIET HA/HB=2/3 . Tinh Saef./Sde

mn giup em nhanh dc ko a em dang can gap  ~~               ~~

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