a,b, Ta co : yot=tox=yox/2=60/2=30
Ma :yox=y'ax=60 (ay'//oy) (dv)
Va : y'at'=t'ax=y'ax/2=60/2=30
Vay : xay' va xat' bang 30
c, ta ca : tox=t'ax=30 (dv)
=> ot//at'
ai biet ve hinh huong dan minh voi nha!
cho góc xOy=30.a thuoc ox qua a dung Ay'//oy (a thouc xoy).goi ot va at' lan luot la tia phan giac goc xoy ;xay'
a) tinh goc oay'
b) chung to ot//at'
Cho xOy=120, Ot la tia phan giac cua xOy. Tren Oy lay diem A. Qua A ve tia At'//Ot va tia Ax'//Ox
1) Tinh xOt va tOy
2) Tinh yAt' va yAx'
Cho goc xOy=120 do va Ot la tia phan giac cua goc do tren tia Oy lay diem A qua A dung duong thang At' song song voi Ot a) Tinh goc yAt' b) Tu A dung duong thang Ax' song song voi Ox so sanh goc t'Ax' va goc tOx
Cho goc xOy, ve tia phan giac Ot cua goc xOy, tren tia Ot lay diem M bat ky, tren cac tia Ox, Oy lan luot lay cac diem A, B sao cho OA=OB.
goi H la giao diem cua AB va ot. CM:
a) MA= MB
b) OM la duong trung truc cua AB
c) biet AB= 6cm, OA= 5cm. tinh OH ?
d) goi C la giao diem cua AM va tia Oy, D la giao diem cua BM va tia Ox. CM: AB//CD
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 goc nhon xoy. diem H nam tren tia phan giac cua goc xoy. tu H dung cac duong vuong goc xuong hai canh Ox va Oy (A thuoc Ox va B thuoc oy).
a.chung minh tam giac hab la tam giac can
b.Goi D la hinh chieu cua A tren tia Oy,C la giao diem cua AD vs OH. Chung minh BC vuong goc vs Ox
c.Khi goc xOy=60 do,chung minh OA=2OD
cho xOy = 120 do va Ot la tia phan giac cua goc do.tren tia Oy lay diem A ,qua A dung dthang At'//Ot
a tinh goc yAt'
b TU A dung duong thang Ax'//Ox.so sanh 2 goc t'Ax' va tOx
Ve goc xOy < 90ova tia phan giac Ot. Lay diem A thuoc Ox va B thuoc Oy sao cho OA=OB. C la diem bat ky tren Ot
1, CM tam giac CAB can
2, OC cat AB o D. Tinh goc ADO
cho xOy =120 do , ve tia oz nam giua 2 tia ox va oy sao cho xOz=24 do. goi tia ot la tia phan giac yOz . tinh xOt
