goi M la 1 diem bat y cua doan thaang AB , diem M nam o dau hay chon cau tra loi dung
a) diem M phai trung voi diem A
b) diem M phai trung voi 2 diem A va B
c) diem M phai trung voi diem B
d) diem M hoac trung voi diem A hoac nam giua 2 diem A va B hoac trung voi diem B
Điểm M có thể nằm bất kì ở đâu trên đoạn thẳng AB nên mình chọn câu d )
d ) Điểm M hoặc trùng với điểm A hoặc nằm giữa A và B hoặc trùng với điểm B
Theo mình chứ không chắc chắn , bạn nhé !
Chúc bạn học tốt ! 
cho doan thang AB dai 3 cm.goi c la trung diem cua AB.tren tia doi cua tia BA lay diem D sao cho B la trung diem cua CD
a) so sanh AD va BC
b) goi M la trung diem cua BC.Diem M co phai la trung diem cua doan thang AD khong?? vi sao
Tra loi giup minh nha cac bn
cho doan AB=12cm.diem M nam giua 2 diem Ava B sao cho AM = 2MB
goi N laf trung diem cua doan AM
chung minh M la trung diem cua doan NB
Ve diem P sao cho B la trung diem cua MP
Diem M co phai la trung diem cua doan AP khong. vi sao
Cho doan thang AB =5cm ,goi I la trung diem cua AB .Tren tia BA ,lay diem M sao cho BM =7cm,tren tia AB lay diem N sao cho AN=7cm .I co phai la trung diem cua MN khong ?Tai sao?
Giup minh voi minh dang can gap
tren tia ox lay 2 diem a b sao cho ob=12cm oa=6cm
a. diem A co phai la trung diem cua doan thang OB ko
b. goi I la trung diem cua doan thang AB. tinh do dai doan thang OI
c. M la diem thuoc tia doi cua tia OB. biet khoang cach giua hai diem M va I la 12cm
tren tia ox lay 2 diem a b sao cho ob=12cm oa=6cm
a. diem A co phai la trung diem cua doan thang OB ko
b. goi I la trung diem cua doan thang AB. tinh do dai doan thang OI
c. M la diem thuoc tia doi cua tia OB. biet khoang cach giua hai diem M va I la 12cm
a: Vì OA<OB
nên điểmA nằm giữa O và B
mà OA=1/2OB
nên A là trung điểm của OB
b: BI=AB/2=3cm
=>OI=9cm
Cho doan thang AB , diem O nam giua A va B . Ke tia Ox vuong goc voi AB . tren tia OX lay cac diem C,D sao cho OC = OA , OD =OB . Goi M la trung diem cua AD , N la trung diem cua BC . Chung minh rang :
a. AD = DC
b. ON = OM , OM vuong goc voi ON .
Cau 5: Trong cac khang dinh sau, khang dinh nao dung, khang dinh nao sai?
1.Ba diem phan biet la ba diem thang hang.
2.Voi ba diem phan biet luon co hai diem nam ve cung phia doi voi diem con lai.
3.Voi ba diem thang hang phan biet luon co hai diem nam khac phia voi diem con lai.
4.Voi ba diem A,B,C thang hang thi diem B luon nam giua hai diem A,C.
5.Co mot va chi mot duong thang di qua hai diem (phan biet) cho truoc.
6.Hai duong thang phan biet thi song song voi nhau.
7.Hai tia chung goc thi cung nam tren mot duong thang.
8.Hai tia chung goc thi doi nhau
9.Neu diem M nam giua diem A,B thi no la trung diem cua doan thang AB.
10.Neu MA=MB thi M la trung diem cua doan thang AB.
11.Neu MA+MB= AB va MA=MB thi M la trung diem cua doan thang AB.
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1. Cho doan thang AB = 16cm.Goi M la trung diem cua AB. Tren doan thang thang Ab lay hai diem C,D sao cho AC = BD = 5cm
a) tính CD
b) Diem M co phai la trung diem cua CD khong. Vi sao?
