cho 99 diem tren mat phang trong do co 2 diem A va B cach nhau 3 cm. Moi nhom3 diem bat ki cua cac diem da cho bao gio cung co the chon ra 2 diem co khoang cach nho hon 1 cm. ve duong tron (A 1 cm)(B 1 cm). CMR trong 2 duong tron do co mot duong tron chuait nhat la 50 diem trong cac diem da cho.

 bai 1 : cho 3 diem V, A , T thang hang . diem nao nam giua 2 diem con lai neu :

TV + VA = TA 

bai 2 : tren 1 duong thang , hay ve 3 diem V , A , T sao cho TA = 1 cm , VA = 3 cm . hoi diem nao nam giua 2 diem con lai 

1/Ve tia ox ;tren tia Ox ve diem A sao cho OA =a cm;ve diem B sao cho OB = 2 a (cm).

a/Trong 3 diem O ; A ;B diem nam giua  2diem con lai ?vi sao?Tinh AB theo a

b/Giai thich vi sao diem a la trung diem doan AB.

c/Goi I la trung diem doan AB. tinh OI theo a​

cho mot duong thang a.ve 1 dem a thuoc duong thang a.ve mat duong thang b di qua diem a.cho diem b nam tren duong thang b.ve mot duong thang c di qua diem a va b.cho diem c nam giua diem a va diem b.hoi diem c nam o duong thang nao

cho doan thang AB=6cm. lay diem M nam giua A va B sao cho AM = 1/3 . tren tia MB lay diem I sao cho MI=1/2 AM .Hãy chung to rằng diem I ko la trung diem cua MB nhung I la trung diem cua AB

HElp me

tren duong thang xy lay 1 diem O va 2 diem M , Nsao cho OM = 2cm ; OB = 3cm. Ve cac diem A va B sao cho M la trung diem cua OA  , N la trung diem cua OB.

giup minh nha!

1 . cho 4 diem A,B,C,D thang hang do :

 ke ten cac truong hop 1 diem nam giua 2 diem con lai .

Cho 20 diem,trong do co a diem thang hang,cu 2 diem,ta ve 1 duong thang.Tim a,biet ve duoc tat ca 171 duong thang

cho 20 diem trong do co A diem thang hang . Cu 2 diem ta ve duoc 1 duong thang . tim A biet ve duoc 170 duong thang

Cho 20 diem,trong do co a diem thang hang,cu 2 diem,ta ve 1 duong thang.Tim a,biet ve duoc tat ca 171 duong thang