cho 2 duong thang xy//mn ,duong thang A cat 2 duong thang xy va mn lan luot tai A va B. ke tia phan giac cua foc xAB va phan giac cua goc ABM chung cat nhau tai C. Ke tia phan giac cua BAI va tia phan giac cua ABN chung cat nhau tai D.chung minh: a)AC vuong goc voi AD, BD vuong goc voi BC
cho tam giac abc co goc a = 90 do.tren nua mat phang bo khong chua C ve tia Bx co bo la AB sao cho AB la tia phan giac cua cua goc CBx.Qua C ve mot duong thang vuong goc voi AC.Tia Bx cat duong thang AC tai D.Duong thang C cat BD tai E.Tia phan giac cua goc CBE cat duong thang CE tai F.C/M
a.AB//CE
b.goc BEC=goc CBE
c.BF\(\perp\)CE
THANK YOU EVERYONE
cho tam giac ABC vuong tai A co B= 30
a, tinh C
b, ve tia phan giac goc C cat canh AB tai D. tren canh CB lay diem Msao cho CA=CM. chung minh ΔACD=ΔMCD
c, qua C ve duong thang xy vuong goc voi CA. tu A ke duong thang song song voi CD cat xy o K. cm AK=CD
d, tinh goc AKC
Cho hai goc ke bu xOy va yOx'. Ve Oz, Ot lan luot la tia phan giac cua goc xOy va yOx'. Ve duong thang mm' vuong goc voi Oz tai K. Chung minh: Ot//mm'
cho tam giac abc co a=2b . tia phan giac cua goc a cat bc o d . ve DE//AB, cat AC o E.Ve EF//ad,cat bc.ve FG//DE, cat AC o D.
a)Nhung goc dinh a,d,e,f nao bang b
b)de,ef,fg la phan giac cua nhung goc nao, vi sao?
Cho tam giac ABC co CAB=ABC. Ve CD la tia doi cua tia CB. Tren nua mat phang bo BC chua diem A ve tia CM//AB. Chung minh rang tia CM la tia phan giac cua goc ACD
Cho góc nhọn xOy. Out la tia phan giac Lấy điểm A thuộc tia Ox, lấy điểm B thuộc tia Oy sao cho
OA = OB. ABcat Out tai M
a)CM:tam giac AOB=tam giacBOM
b)CM:AM=BM
c)H thuoc Out,qua H ke duong thang song song voi AB, duong thang nay cat Ox tai C, Oy tai D.CM:OH vuong goc voiCD
Cho hai goc ke bu xOy va yOz. Ve Om, On lan luot la tia phan giac cua cac goc xOy va yOz. Tu diem A tren Oy ve cac tia vuong goc voi Om, On lan luot cat Ox, Oz tai B va C. Tinh so do goc BAC
Cho tam giac ABC co B=C. Ve tia AD la tia doi cua tia AB. Tren nua mat phang bo AB chua C ve tia AM//BC. Chung minh AM la tia phan giac cua goc DAC
