cho 5 diem A B C D E sao cho 3 diem a b c thang hang ba diem b c d thang hang ba diem b c e khong thang hang a) giai thich vi sao ba diem a b d thang hang? b)ke duong thang moi duong thang di qua it nhat 5 diem tren c)ke ten cac duong thang trong hinh ve

cho 4 diem a b c d trong do ko co 3 diem nao thang hang .Tim diem O sao cho 3 diem a o c thang hang va 3 diem b o d thang hang

Cho 4 diem A,B,C,D trong do ko co 3 diem nao thang hang (doan nay doc co ve de ).Tim diem O sao cho 3 diem A,O,C thang hang va diem B,O,D thang hang(doc xong chac thay om lun)

cho 4 diem A, B, C, D phan biet cu qua 2 diem ta ve dc 1 duong thang . Hoi ve duoc bao nhiu duong thang biet rang trong 4 diem phan biet ko co 3 diem nao thang hang

Ve 5 diem A,B,C,D sao cho 3 diem A,B,C thang hang, 3 diem B,C,D thang hang, 3 diem C,D,E khong thang hang

a) Giai thich vi sao 3 diem A,B,D thang hang

b) Tren hinh ve hay tim diem nam giua 2 diem con lai

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?

Ve tren cung mot hinh theo cach dien dat sau :

a)Ve 4 diem A ,B ,C D sao cho C nam giua A, B va 3 diem A, B D ko thang hang . Hay ve va ke ten duong thang (phan biet) di qua tung cap diem .

b) Ve diem E sao cho E va D nam khac phia doi voi A . Ve diem F sao cho C,E,F thang hang va F thuoc duong thang DB

ve : a) ba diem m,n,p thang hang .b)ba diem c,e,d thang hang sao cho diem e nam giua hai diem cvad .c)ba diem t,q,r khong thang hang

cho duong thang xy.tren duong thang xy co 2017 diem,3 diem a,b,c khong thuoc duong thang xy va ko thang hang va bat ki diem nao tren dương thang xy deu khong thang hang voi hai trong ba diem a,b,c.qua hai diem bát ki nguoi ta ke mot duoc thang.hoi co bao nhieu duong thang?