1. Tren 1 duong thang xy lay 4 diem phan biet A,B,C,D hay chi ra cac tia doi nhau 

2. cho 10 diem trong do khong co ba diem thang hang . Cu qua hai diem ta ve duoc 1 duong thang . Hoi co tat ca bao nhieu duong thang?

3. cho n diem trong do khong co ba diem nao thang hang . Cu qua hai diem trong so cac diem do ve duoc 1 duong thang. Biet rang co 435 duong thang tao thanh .Tim n?

cho truoc 1 so diem trong do ko co 3 diem thang hang .ve cac duong thang di qua cac cap diem .biet tong so cac duong thang ve duoc la 36 . tinh so diem cho truoc .

cho 15 diem phan biet (trong do ko co 3 diem nao thanh hang) ,cu qua hai diem ve duoc 1 duong thang. tinh so duong thang di qua cac cap diem

- Ve va ke ten cac doan thang co hai dau mut trong so cac diem M,N,P,Q

- Ve cac duong thang,moi duong di qua hai trong so cac diem M,N,P,Q. Khi do ke ten cac duong thang phan biet

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Cho truoc n diem trong do ko co 3 diem nao thang hang.Ve cac duong thang di qua cac cap diem,Tim n biet rang neu co them 1 diem(ko thang hang voi bat ki 2 diem nao trong so n diem da cho) thi so duong thang ve duoc tang them la 8.

Minh dang can gap!Cac ban giup minh voi nhe!

cho truoc n diem trong do k co 3 diem nao thang hang ve duong thang di qua cac cap diem. Tim n biet rang neu co them 1 diem (k thang hang voi bat cu 2 diem nao trong tong so n diem da cho) thi so duong thang ve dc tang them 8 duong 

cho 20 diem phan biet , trong do co dung 7 diem thang hang , ngoai ra khong co 3 diem nao thang hang.cu qua 2 diem ta ve duoc 1 duong thang.hoi tu 20 diem do ta ve duoc bao nhieu duong thang

cho 7 diem trong do co dung 4 diem thang hang cu qua 2 diem ta ve duoc 1 duong thang so duong thang da ve la

cho 50 diem trong do co dung m diem thang hang , ngoai ra ko co 3 diem naop thang hang. cu qua 2 diem ta ve duoc 1 duong thang .so duong thang ve duoc la 1215 duong thang.tim m