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 nhon xOy co Ot la tia phan giac. Lay diem A tren tia Ox, diem B tren tia Oy sao cho OA=OB. Ve doan thang AB cat tia Ot tai M. a) Chung minh: tam giac AOM=tam giac BOM, b)chung minh AM=BM, c) chung minh: OM vuong goc voi AB
cac ban oi giup minh voi nhaaaaaaaaaaaaaaa
bai 1 cho goc xoy ve tia phan giac cua goc xoy tren tia ot lay diem m bat ki tren cac tia õ va oy lan luot la lay cac diem a va b sao cho oa =ob goi h l giao diem cua ab va ot . chung minh :
a,ma=mb
b,om la duong trung truc cua ab
c,cho biet ab=6cm oa=5cm tính oh
bai 2 cho tam giac abc co ba goc goc goc nhon duong cao ah vuong goc voi bc tai h tren tia doi cua tia ha lay diem d sao cho ha=hd
cmr:a,bc va cb lan luot la cac tia phangiac cua goc abd va acd
b,ca=cd va bd=ba
c,cho goc acb 45 độ tính góc adc
d, duong cao ah phai them điều kiện gi thi ab song song cd
bai 3 cho tam giac abc co ab =ac ke bd vuong goc ac ce vuong goc ab goi o la giao diem cua bd va ce cmrang
a,bd=ce
b,tam giac oeb=tam giac odc
c,ao là tia phân giác của góc bac
Bài1: cho góc xOy va tia phan giac Ot. Trên tia Ot lay điểm M bat ky ; tren cac tia Õ va Oy lan lupt lay cac diem A va B sao co OA = OB; goi H la giao diem cua AB va Ot. C/m
a) MA=MB
b) OM la duong trung truc cua AB
c) Cho biet AB= 6cm, OA= 5cm. Tinh OH
cho goc nhon XOY lay diem A thuoc tia OX lay diem B thuoc tia OY sao cho OA=OB qua A ke duong thang vuong goc voiOX catOYtai M qua B ke duong thang vuong goc voi OY cat OX tai N goi H la giao diem cua AM va BN ,I la trung diem cua MN. CMR :
a) ON=OM va AN=BM
b) tiaOHla tia phan gic cua goc XOY
C)ba diem O,H,I thang hang
Cho goc xOy khac goc bet. Tren tia phan giac Ot cua goc xOy lay diemC,ke duong thang d vuong goc voi ot tai C,va cat Ox,Oy lan luot taiA,B.Chung minh rang:
a,Tam giac AOC bang tam giac BOC
b, OA = OB
c,Lay diem d thuoc tia Ot(D khac C).Chung minh AD bang BD, goc OAD bang gocOBD
Lay diem C € tia p/giac Oz cua goc xOy. Ke CA va CB lan luot voi vuong goc voi Ox va Oy (A€ Ox, B € Oy)
a, chung minh ∆AOC va ∆BOC
b, chung minh OC la duong trung truc cua dg thang AB
c, ke AD vuong goc voi OB( D€OB) goi M la giao diem cua AD voi Oz ,chung minh BM vuong goc voi OA
Cho goc xOy khac goc bet. Tren tia Ox lay cac diem A,B sao cho OA<OB. Tren tia Oy lay cac diem C,D sao cho OC=OA, OD=OB.a) Chung minh rang AD=BC, b) Goi E la giao diem cua AD va BC.Chung minh rang tam giac AEB=tam giac CED
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