cho N diem(n lon hon hoac bang 2).hoi ve duoc bao nhieu doan thang
Cho n diem cu noi 2 diem ta ve duoc mot doan thang.
a)Hoi co tat ca bao nhieu doan thang
b)Tim n biet so doan thang ve duoc la 55
Cho n diem (n thuoc N va n lon hon 1).Ve cac doan thang di qua cac cap diem duoc so doan thang nhieu hon 406 doan thang nhung it hon 465 doan thang .Tim n
Cho N diem trong mat phang qua 2 diem ta ve duoc 1 doan thang va tat ca co duoc 21 doan thang . Tim so diem da cho
cho n diem (n la so tu nhien lon hon1) cu 2 diem ta dc 1 doan thang. Hoi n bang bao nhieu de co so doan thang bang tong cac so tu nhien tu 1 den 99?
Cho 5 diem A, B, C, D, E phan biet. Cu qua hai diem ta ve duoc 1 doan thang. Hoi co tat ca bao nhieu doan thang ?
cho n diem(n.).cu qua 2 diem ta ke 1 doan thang.
a,co bao nhieu doan thang?
b,tinh n biet co tat ca 105 doan thang?
cho truoc 1 so diem.Cu cho 2 diem ve duoc 1 doan thang.Biet rang co tat ca 2016 doan thang.Hoi co bao nhieu diem cho truoc
trong mat phang cho 10 diem phan biet, trong do khong co 3 diem nao thang hang.Hoi co the ve duoc bao nhieu tia, bao nhieu doan thang, bao nhieu duong thang? (neu trong diem phan biet do co 5 diem thang hang thi ve duoc bao nhieu tia, bao mhieu doan thang, bao nhieu duong thang).