Cho 21 diem.Qua 2 diem ve duoc 1 doan thang.Co tat ca bao nhieu doan thang?
Thay 21 diem boi n (n thuoc N,n lon hon hoac bang 2) so doan thang co duoc la bao nhieu?
cho N diem(n lon hon hoac bang 2).hoi ve duoc bao nhieu doan thang
a) ve nam diem M,N,P,Q,R sao cho ba diem M,N,P thang hang,ba diem N,P,Q thang hang ,con ba diem N,P,R khong thang hang b) ke cac duong thang di qua cac cap diem.Co bao nhieu duong thang,ke ten cac duong thang do c)co bao nhieu doan thang?ke ten cac doan thang do d)ke ten cac tia goc P.Trong cac tia do chi ra hai tia doi nhau ? hai tia trung nhau?
cho 5 diem a b c d e. trong do khong co ba diem nao thang hang.hoi ve duoc bao nhieu doan thang di qua cac cap diem.ke ten cac doan thang do
b\neu 5 diem thang hangthi ket qua thay doi khong
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 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 cac diem A va B thuoc duong thang a,diem C nam giua A va B.diem D nam giua C va B.cau hoi;a,tim tren hinh ve cac tia doi nhau goc C.b,dung lap luan chung to C nam giua A va B.c,tren hinh ve co bao nhieu doan thang?la nhung doan thang nao
Cho diem n phan biet . Noi tung cap hai diem trong n diem do thanh cac doan thang . Tim so diem n , biết rang co tat ca 28 doan thang
Moi nguoi giai giúp minh nha
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?