Cho goc xOy = 90 trong goc xOy ve tia OC,OD sao cho aOc=bOd=60 voi a thuoc ox va b thuoc oy
a)tinh so do cua goc aod,doc,cob
b)tren nua mat phang bo oa co chua tia ob ve tia oe sao cho ob la phan giac cua goc doe
chung to OE vuong goc OC
cho goc xoy =50 do. lay diem A tren tia ox . tren cung 1 nua mat phang bo ox chua tia oy, ve tia ot sao cho oy cat nhau tai B va goc oAt =80 do. goi at' la tia phan giac cua goc xAt
a) chung minh At'song song voi Oy
b) tren nua mat phang ko chua diem A bo duong thang oy ve tia Bn song song Ox
Cho Ox va Oy la hai tia doi nhau.Tren cung mot nua mat phang bo la duong thang xy ve hai tia Oz va Ot sao cho goc xOz=150 do;goc yOt=60 do.
a)Tinh so do goc xOt.
b)Chung to Oz la tia phan giac cua goc yOt.
c)Tren nua mat phang co chua tia Oz bo la duong thang xy ve tia Om sao cho goc zOm=90 do.Hoi tia Om co la tia phan giac cua goc xOt hay khong?Vi sao?
cho goc xoy = 140 do , tren tia ox , lay diem a ve tia Az sao cho tia Az va tia oy nam tren cung 1 nua mat phang bo chua tia ox va goc oaz = 40 do . a) CMR Az song song oy b) ve tia Az' la tia doi cua tia Az . CMR 2 duong thang phan biet cua 2 goc xoy va goc oaz song song voi nhau
cho xOy la goc nhon biet Oz la tia phan giac cua xOy tren nua mat phang bo Ox ta lay A tren nua mat phang Oz lay I tren nua mat phang Oy ta lay B ao cho AB cat IO tai H va AH=HB
a)CM AIH=IBH
b)CM AOH=BOH
c)CM AIH và IBH vuong goc
cho tam giac ABC nhon tren nua mat phnag co chua A bo BC ve tia Bx vuong goc voi BC tren tia do lay D sao cho BD=BC tren nua mat phang co hcua diem C bo AB ve tia By vuong goc voi AB tren tia do lay diem E sao cho BE=BA goi giao diem cua DA voi BC va EC theo thu tu la H,K tinh goc BKA
tren cung mot nua mat phang bo chua tia Ox ve cac tia Oy Oz,Ot sao cho xOy <xOz<xOt<180• va co xOz =yOt A,B,C,D khac 0 lan luot la cac diem tren tia Ox ,Oy ,Ot sao cho OA=Oc ,OB = OD
a,c/m goc AOB =goc COD
b,goi Om la tia phan giac cua goc AOD chung minh Om la tia phan giac cua goc BOC
help me
cho goc xoy = 140 do , tren tia ox , lay diem a ve tia Az sao cho tia Az va tia oy nam tren cung 1 nua mat phang bo chua tia ox va goc oaz = 40 do .
a) CMR Az song song oy
b) ve tia Az' la tia doi cua tia Az . CMR 2 duong thang phan biet cua 2 goc xoy va goc oaz song song voi nhau
Cho goc bet xOy.Tren cung mot nua mat phang xy, ve tia Ot,Oz sao cho xOt=yOz=30'
a)Tinh so do goc tOz
b)Ve tia phan giac Om cua goc tOz.Tia Om co phai la tia phan giac cua goc xOy khong?Vi sao?