cho tam giac ABC co goc A =60 do, goc B= 70 do. Ve tia phan giac cua goc A cat canh BC tai D.Tinh goc ADC, ADB
Cho tam giac ABC co goc B - goc C = 20 do. tia phân giac cua goc A cat BC tai D. Tính goc ADB va goc ADC ?
cho tam giac abc co goc b = goc c, tia phan giac cua goc a cat bc tai d
1. chung minh tam giac adb = tam giac adc
2. chung minh ad vuong goc voi bc
3. tren tia doi cua tia da lay diem m sao cho da = dm, chung minh ab // cm
cho tam giac ABC co B-C=a, tia phan giac cua goc A cat CB tai D. Cau a : tinh ADC,ADB . Cau b: ve AH vuong goc voi BC, tinh HAD
cho tam giac ABC co goc B = 80 do, goc C =30 do . tia phan giac cua goc A cat BC o D . tinh doc ADC, goc ADB
cho tam giac aBC vuong tai A co goc B=30 do, AB=6cm,Tia phan giac goc C cat AB tai D.Tinh AB va BD
cho tam giac ABC co B=C tia phan giac cua goc A cat BC tai D chung minh rang
a)tam giac ADB=tam giac ADC
b)AB=AC
Cho tam giac ABC co B^=C^.Tia phan giac cua goc A cat BC tai D. Chung minh rang:
a)Tam giac ADB=tam giac ADC
b)AB=AC
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