Tren duong thang AA lay diem O . tren mot nua mat phang bo AA vi tia OB , tren nua mat phang con lai ve OC sao cho AOB =AOC=150
a)Tinh BOC ?
b)Tia OA co phai la tia phan giac cua goc BOC ko ? vi sao ?
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Tren duong thang AA' lay diem O .Tren mot nua mat phang bo AA' ve tia OB sao cho goc AOB = 45o,tren nua mat phang con lai ve tia OC sao cho goc AOC = 90o.
a.Goi OB' la tia phan giac cua goc A'OC. Chung to rang hai goc AOB va A'OB' la hai tia doi dinh.
b. Tren nua mat phang bo AA' co chua OB ve OD sao cho goc BOD =90o. Tinh A'OD.
Tren duong thag a lay ba diem A,O,A'(O nam giua A va A').Ve tia OB sao cho AOB=45°,tren nua mat phang co bo la duong thang a khong chua tia OB ve tia OC sao cho AOC=90°
a.Goi OB' la tia phan giac cua goc A'OC.Chung minh rang:hai goc AOB va A'OB' la hai goc doi dinh
b,Tren nua mat phang co bo la duong thang a chua tia OB ve tia OD sao cho BOD=90°.Tinh so do goc A'OB'
tren cung mot nua mat phang co bo chua tia OA ve hai tia OB va OC sao cho goc AOC = 40° AOB =110° a,tinh so do goc BOC b,ve tia OD la tia doi cua tia OA Tinh so do goc ke bu voi goc AOB c,tia OB co la tia phan giac cua goc COD ko ?vi sao
a/tren cung 1 nua mat phang bo chua tia OA tia OC nam giua 2 tia OA, OB vi goc AOC< goc AOB (40 do< 110 do)
ta co:goc BOC + goc AOC = goc AOB
suy ra goc BOC + 40 do= 110 do
suy ra goc BOC = 110 do - 40 do = 70 do
vay goc BOC = 70 do
b/ vi tia OD la tia doi cua tia OA nen :
goc BOD + goc BOA = 180 do
suy ra goc BOD + 110 do= 180 do
suy ra goc BOD = 180 do - 110 do = 70 do
vay goc BOD = 70 do
c/ tia OB co phai la tia phan giac cua goc COD vi goc BOC = BOD (= 70 do) va tia OB nam giua 2 tia OC, OD
mik chua chac dung dau vi mik nam nay moi vao lop 7 nhung nho k cho mik nha
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Tren cung mot nua mat phang bo cua tia OA ve tia OB sao cho aOb =40 ve tia OC sao cho aOc =80
Tia OB co phai la tia phan giac cua goc aOc khong ? Vi sao
Ve tia OD la tia phan giac cua goc aOb tia OM la tia phan giac cua goc bOd. Neu ten cac goc ke bu
bai 1: tren mot nua mat phang bo chua tia Oa ve tia Ob sao cho goc AOB=35 do va tia Oc sao cho goc AOC= 70 do
a, tia Ob co phai la tia phan giac cua goc AOC khong? vi sao?
b, ve tia OB` la tia doi cua tia OB. tinh so do goc ke bu voi goc AOB
Cho tia OB. Tren hai nua mat phang doi nhau bo chua OB. Ve hai tia OA va OC SAO CHO goc AOB = BOC = 25o. Ve tia OB' la tia doi cua tia OB. Trong hai tia OB va OB' tia nao la tia phan giac cua goc AOC? Vi sao?
Cho goc bet AOB. Tren cung mot nua mat phang bo AB, ve hai tia OC va OD sao cho AOD=BOC=30 do.
a/Hai goc AOD va BOC co phai la hai goc doi dinh khong/ Vi sao?
b/ Ve tia OM sao cho tia OA la tia phan giac cua goc DOM.Chung minh rang hai goc AOM va BOC la hai goc doi dinh
tren nua mat phang bo chua tia Oa ,ve hsi tia Ob va Oc sao cho goc aOb =150 do ,goc aOc =90 do .Om la tia pham giac cua goc aOc
On la tia phan giac cua goc bOc
a) chung to rang Oc nam giua Oa,Ob
b) tinh so do cac goc bOc=?,aOm=?,aOn=?,mOn=?
Bai 1: Tren duong thang AB lay diem O. Tren nua mat phang bo AB ve 2 tia OC va OD sao cho widehat{AOC}widehat{BOD}60^0
a, Hoi widehat{AOC} va widehat{BOD}co la 2 goc doi dinh khong? Vi sao?
b, Tren nua mat phang bo AB khong chua tia OD.Ve tia OE sao cho OB la tia phan giac cua widehat{DOE}. Hoi AOC va widehat{BOE} co la 2 goc doi dinh khong? Vi sao?
Bai 2: 2 duong thang xx phay cat yy phay tai A sao cho widehat{xAy}47^0. Tinh 3 goc con lai.
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Bai 1: Tren duong thang AB lay diem O. Tren nua mat phang bo AB ve 2 tia OC va OD sao cho \(\widehat{AOC}=\widehat{BOD}=60^0\)
a, Hoi \(\widehat{AOC}\) va \(\widehat{BOD}\)co la 2 goc doi dinh khong? Vi sao?
b, Tren nua mat phang bo AB khong chua tia OD.Ve tia OE sao cho OB la tia phan giac cua \(\widehat{DOE}\). Hoi \(AOC\) va \(\widehat{BOE}\) co la 2 goc doi dinh khong? Vi sao?
Bai 2: 2 duong thang xx phay cat yy phay tai A sao cho \(\widehat{xAy}=47^0\). Tinh 3 goc con lai.
Bài 2:
\(\widehat{xAy}=\widehat{x'Ay'}=47^0\)(hai góc đối đỉnh)
\(\widehat{xAy'}=180^0-\widehat{xAy}=133^0\)(hai góc kề bù)
=>\(\widehat{x'Ay}=133^0\)(hai góc đối đỉnh)
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