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 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
ta có\(\widehat{OAt}+\widehat{tAx}=\widehat{OAx}\)
thay\(80^o+\widehat{tAx}=180^o\)
\(\widehat{tAx}=180^o-80^o=100^o\)
vid tia At' là tia phân giác của tAx
\(\Rightarrow\widehat{tAt'}=\widehat{t'Ax}=\frac{\widehat{xAt}}{2}=\frac{100^o}{2}=50^o\)
\(\Rightarrow\widehat{xAt'}=\widehat{xOy}=50^o\)
hai góc \(\widehat{xAt'}\)và\(\widehat{xOy}\)ở vị trí đồng vị bằng nhau
\(\Rightarrow Oy//At'\)
b)
lay diem O batcky tren xy. tren nua mat phang bo xy, ve tia Ozcsao cho goc xoz = 50 do. tren tia Oy, lay diem B. tren nua mat phang bo xy chua tia Oz , ve Bt sao cho goc tBy= 130 do :
a) chung minh Oz song song Ot
b) ve tia Om va Bn lan luot la tia phan giac cua goc xoz va goc xbt. chung minh Om song song Bn
Tren cung mot nua mat phang bo chua tia Ox, ve 2 tia Oy va Oz sao cho goc xOy =30 do va goc xOz =105 do
a) Trong 3 tia Ox, Oy, Oz tia nao nam giua 2 tia con lai? Vi sao?
b) Ve tia Ot la tia doi cua tia Ox. Tinh so do goc cua goc yOz va zOt
c) Tia Oz co la tia phan giac cua goc yOt khong? Vi sao?
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
TREN CUNG MOT NUA MAT PHANG CO BO CHUA TIA Ox VE HAI GOC xOy,yOz KE BU NHAU SAO CHO GOC xOy=80 DO
A] TINH GOC yOz
B] GOI Om , On LA CAC TIA PHAN GIAC CUA GOC xOy VA GOC yOz . CHUNG TO GOC mOm LA GOC VUONG
C] TREN NUA MAT PHANG KO CHUA TIA Oy CO BO CHUA TIA Ox , VE TIA Oc SAO CHO GOC xOt=80 DO . TINH mOt
cho xOy =120 do lay diem Atren tiaOx tren cung nua mat phang chua tia Oy bo Ox ve tia At sao cho OAt = 60 do goi At' la tia doi cua tia At
a)chung to tt' song song vs Oy
b) goi Om va An theo thu tu la tia phan giac cua xOy va xAt chung to Om song song vaAn
tren cung 1 nua mat phang co bo la duong thang chua tia Ox ve 2 tia Oy va Oz sao cho goc xOy=60do xOt = 100 do
trong 3 tia Ox Oy Oz diem nao nam giua 2 tia con lai
tinh so do goc yOz
Vì \(\widehat{xOy}< \widehat{xOt}\left(60^o< 100^o\right)\)
=> Tia Oy nằm giữa 2 tia Ox và Oz
=> \(\widehat{xOy}+\widehat{yOt}=\widehat{xOt}\)
=> \(\widehat{yOt}=100^o-60^o=40^o\)
tren cung mot nua mat phang co bo chua tia ox , ve hai tia oy va oz sao cho goc xoy = 100,xoz = 20
a, tinhso do goc yoz
b,ve tia om la tia phan giac cua goc yoz.tinh so do goc xom
tren cung mot nua mat phang co bo chua tia ox , ve hai tia oy va oz sao cho goc xoy = 100,xoz = 20
a, tinhso do goc yoz
b,ve tia om la tia phan giac cua goc yoz.tinh so do goc xom
