cho goc xoy va tia phan giac oz, tren tia ox lay diem a, tren tia oy lay diem b sao cho oa=ob. lay diem i tren tia oz (i#o)
a/ chung minh tam giac oai bang tam giac obi
b/doan thang ab cat oz tai h. chung minh h la trung diem cua ab
c/chung minh ab vuong goc voi oz
Bai 5: Cho goc xOy nhon, Ot la tia phan giac cua xOy. Tren tia Ot lay diem H, qua H ve duong thang vuong goc voi Ot cat Ox tai A, cat Oy tai B.
a/ Chung minh \(\Delta AHO=\Delta BHO\)
b/ Tren tia Ax lay diem C, tren tia By lay diem D sao cho AC=BD. Chung minh AD=BC
c/ CD cat tia ot tai K. Chung minh AB / / CD
mn giup em vs ak
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
Cho goc nhon xoy . Tren tia Ox lay AB , tren tia Oy lay 2 diem C va D sao cho CA=OC,OB=OD
a,Chung minh : AD=BC
b,Gia su AD cat BC tai I. Chung minh tam giac AIB=tam giac CID
c,Chung minh :OI la tia phan giac cua goc xoy
cho tam giac nhon ABC, ve BD vuong goc AC tai D va CE vuong goc AB tai E. Cac duong thang BD va CE cat nhau tai H. Goi diem M la trung diem cua canh CB. Tren tia doi cua tia MH lay diem K sao cho MH=MK. a) chung minh: tam giac BMH=tam giac CMK, b) chung minh: CK vuong goc AC, c) ve HI vuong goc BC tai I, tren tia HI laydiem G sao cho HI=IG. Chung minh: GC=BK
cho tam giac ABC co goc a nhon M la trung diem cua BC tren tia doi cua tia MA lay diem D sao cho MA=MD chung minh BAM=CDM chung minh AC=AD tren nua mat phang Bo AB ko chua C ve tia Ax vuong goc AB tren nua mat phang bo AC ko chua B ve tia Ay vuong goc AC tren tia Ax lay Diem P sao cho AP=AB tren tia Ay lay diem Q sao cho AQ=AC chung minh tam giac ABQ= tam giac APC goi giao diem cua DA va PQ la K chung minh AK vuong goc PQ
Cho tam giac ABC , AB < AC . AE la tia phan giac cua goc BAC (E thuoc BC) . Tren canh AC lay diem M sao cho AM=AB
a) Chung minh tam giac ABE = tam giac AME
b) AE cat BM tai diem I . Chung minh I la rung diem cua BM
c) Tren tia doi cua tia EM lay diem N sao cho EN=EC. Chung minh tam giac ENB = tam giac ECM
d) Chung minh K,B,M thang hang
Cho tam giac ABC , AB < AC . AE la tia phan giac cua goc BAC (E thuoc BC) . Tren canh AC lay diem M sao cho AM=AB
a) Chung minh tam giac ABE = tam giac AME
b) AE cat BM tai diem I . Chung minh I la rung diem cua BM
c) Tren tia doi cua tia EM lay diem N sao cho EN=EC. Chung minh tam giac ENB = tam giac ECM
d) Chung minh K,B,M thang hang
Cho tam giac ABC , AB < AC . AE la tia phan giac cua goc BAC (E thuoc BC) . Tren canh AC lay diem M sao cho AM=AB
a) Chung minh tam giac ABE = tam giac AME
b) AE cat BM tai diem I . Chung minh I la rung diem cua BM
c) Tren tia doi cua tia EM lay diem N sao cho EN=EC. Chung minh tam giac ENB = tam giac ECM
d) Chung minh K,B,M thang hang