Ta có: CM // AB (gt)
\(\Rightarrow\widehat{ACM}=\widehat{CAB}\left(\text{slt}\right);\widehat{DCM}=\widehat{CBA}\left(\text{đv}\right)\)
mà \(\widehat{CAB}=\widehat{CBA}\) (gt)
\(\Rightarrow\widehat{ACM}=\widehat{DCM}\)
\(\Rightarrow\) CM là tia phân giác góc ACD
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
Cho tam giac ABC. Tren nua mat phang bo AB khong chua C ve tia AM sao cho goc MAB=ABC. Tren nua mat phang bo AC khong chua B ve tia AN sao cho goc NAC=ACB. Chung minh AM va AN la hai tia doi nhau.
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 goc AOY=130 va diem A nam tren tia Ox ve tia Ax //Oy [tia Az nam trong goc xOy ]
a, tinh so do goc OAZ
b,ve tia Ot , Av theo thu tu la tia phan giac cua xOy va xAz . chung minh rang Ot //Av
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 2 duong thang ab,cd cat nhau . tai O tao thanh goc nhon AOC . ve tia OE sao cho OA la tia phan giac cua goc COE chung minh goc AOE=BOD
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 2 goc doi dinh xoy va x'oy'. om la tia phan giac cua xoy. On la tia doi cua Om. chung minh On la phan giac x'oy'
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