1) Cho hai doan thang AC.BD cat nhau tai I. Phat bieu nao sau day?
A) Goc BAC va DIC dong vi B) Goc ADB va CBD so le trong
C) Goc BAC va ACD so le trong D) Goc CAD va ACB so le trong
2) Cho tam giac ABC co BAC=90 do. Qua B dung duong thang b vuong goc voi AB va qua C dung duong thang c vuong goc voi AC. Phat bieu nao sau day la sai?
A) b va c cat nhau B) AB//c C) AC//b D) Ca A,B,C deu sai
3) Cho hai duong thang song song a,b. Mot duong thang c vuong goc voi ca hai duong thang a va b. Goi d la mot duong thang bat ky. Phat bieu nao sau day la dung?
A) Neu d khong co diem chung voi a thi cung khong co diem chung voi b
B) Neu d cat a thi d cung cat b
C) Neu d vuong goc voi a thi d song song voi c
D) Ca ba paht bieu tren deu dung.
4) Cho ba diem M,N,P khong thang hang. Phat bieu nao sau day sai?
A) Chi co mot duong thang di qua M va song song voi NP B) Co mot tam giac MNP
C) Chi co mot duong thang di qua M va vuong goc voi NP D) Tat ca deu sai
5) Cho biet hai duong trung truc cua hai doan thang AB va CDD cat nhau tai O. Trong cac cau sau, cau nao dung:
A) AB//CD B) AB\(\perp\)CD C) AB va CD cat nhau D) Tat ca deu sai
cho tam giac abc co goc a = 90 do.tren nua mat phang bo khong chua C ve tia Bx co bo la AB sao cho AB la tia phan giac cua cua goc CBx.Qua C ve mot duong thang vuong goc voi AC.Tia Bx cat duong thang AC tai D.Duong thang C cat BD tai E.Tia phan giac cua goc CBE cat duong thang CE tai F.C/M
a.AB//CE
b.goc BEC=goc CBE
c.BF\(\perp\)CE
THANK YOU EVERYONE
cho 2 duong thang xy//mn ,duong thang A cat 2 duong thang xy va mn lan luot tai A va B. ke tia phan giac cua foc xAB va phan giac cua goc ABM chung cat nhau tai C. Ke tia phan giac cua BAI va tia phan giac cua ABN chung cat nhau tai D.chung minh: a)AC vuong goc voi AD, BD vuong goc voi BC
cho tam giac ABC vuong tai A co B= 30
a, tinh C
b, ve tia phan giac goc C cat canh AB tai D. tren canh CB lay diem Msao cho CA=CM. chung minh ΔACD=ΔMCD
c, qua C ve duong thang xy vuong goc voi CA. tu A ke duong thang song song voi CD cat xy o K. cm AK=CD
d, tinh goc AKC
cho 2 duong thang ab,cd cat nhau . tai O tao thanh goc nhon AOC . ve tia OE sao cho OA la tia phan giac cua goc COE chung minh goc AOE=BOD
cho tam giac abc co a=2b . tia phan giac cua goc a cat bc o d . ve DE//AB, cat AC o E.Ve EF//ad,cat bc.ve FG//DE, cat AC o D.
a)Nhung goc dinh a,d,e,f nao bang b
b)de,ef,fg la phan giac cua nhung goc nao, vi sao?
Cho hai goc ke bu xOy va yOx'. Ve Oz, Ot lan luot la tia phan giac cua goc xOy va yOx'. Ve duong thang mm' vuong goc voi Oz tai K. Chung minh: Ot//mm'
phat bieu tien de o clit ve duong thang song song
Cho tam giac ABC. Tren nua mat phang bo AB khong chua C ve tia AM sao cho goc MAB=ABC. Tren nua mat phang bo AC khong chua B ve tia AN sao cho goc NAC=ACB. Chung minh AM va AN la hai tia doi nhau.