dien vao cho trong cho cac phat bieu sau:

a)hinh tao thanh boi diem O va 1 phan duong thang bi chia ra boi diem Oduoc goi la 1 .......................

b)diem R bat ki nam tren duong thang xy la goc chung cua.............................

c)neu diem A nam giua 2 diem B va C thi:

-hai tia............................doi nhau

-hai tia CA va ..........................................trung nhau

-hai tia BAva BC ...............................

Phat bieu nao dung, phat bieu nao sai?

1/ Co duy nhat mot duong thang di qua 2 diem cho truoc.

2/ Doan thang AB la hinh gom tat ca cac diem nam giua 2 diem A va B

3/ Co 3 diem M, A, B, neu co MA = MB thi M la trung diem cua doan thang AB

Tren duong thang x,y lay o.Lay diem a thuoc tia ox,B thuoc tia oy sao cho OA=2cm;OB=2oa

A)Tinh do dai doan AB?

B)Goi Yla trung diem cua OB.Chung minh O la trung diem cua doan thang AI

C) Tren duong thang xy lay 100 diem diem phan biet(khac O,A,B,I).Noi 2 diem ta duoc mot doan thang.Hoi co bao nhieu duong thang tao thanh?

giup minh voi! HELP ME!!!!!

Cho diem O nam tren duong thang xx'. Tren cac tia OX va OX' lay hai diem A va B khac O. Sao cho AB=12cm. Goi M,N lan luot la trung diem cua OA va OB.

1. Tinh MN. O co la trung diem cua MN ko. Vi sao?

2. Voi dk j thi AB va MN co cung trung diem

cho diem o tren duong thang xy . tren duong thang do dat cac doan oa=2 cm,ob=3cm , roi lay diem e va f sao cho a la trung diem cua doan thang oe, b la trung diem cua doan thang of.tinh do dai doan ef

( sorry cac bn nhe may tinh cua mk ko danh duoc dau  nhung chac cac bn dich ra duoc. thanh that xl nhe )

tren mot duong thang lay 3 diem A,B,C ( C nam ngoai doan AB). Biết AB=8cm;BC=4cm. Goi M,N,I lan luot la trung diem cua cac doan AB;AC;BC. CTR: Cac doan MN va AI co cung 1 trung diem

tren tia Ox lay hai diem A,B sao cho OA = 3cm, OB = 6cm

a) trong ba diem O, A, B diem nao nam giua hai diem con lai

b) Tinh AB

c) Diem A co phai la trung diem cua doan OB khong? vi sao?

d) goi I la trung diem cua doan thang OA, K la trung diem cua doan thang AB. Tinh IK

ai ve hinh duoc thi ve luon ho toi nhe!

Goi M va N la 2 diem nam khac phia doi voi duong thang xy . Doan thang MN cat xy tai O. Tren tia Ox lay diem A sao cho Oa =2cm , goc MAx=NAx=130o.

a) Hoi tia Oy co phai la tia phan giac cua goc MAN?

b)Tren tia Oy lay diem B sao cho MBH=100o , MBO=40o. Tinh NBO

c) goi AC la tia doi cua tia AM.So sanh cac goc CÃ,NAB,NBy?