tiep
Cho n diem ko co ba diem nao thang hang. Qua 2 diem trong so cac diem do ve 1 dg thang. Bt rang co 435 dg thang tao thanh. Tim n
Ghi loi giai
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 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 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!
a/cho 6 diem trong do ko co 3 diem nao thang hang
b/cho 7 diem trong do ko co 3 diem nao thang hang
hoi so dg thang di qua 2 diem la bao nhieu
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
cho 100 diem noi tung cap 2 diem trong 100 diem do thanh cac doan thang tinh so doan thang tao ra nếu trong 100 điểm đó có:
a,ko co 3 diem nao thang hang
b,co dung 5 diem thang hang
c,neu tao ra 105 doan thang thi can bao nhieu diem
cho 100 diem thang hang trong do co dung 4 diem thang hang cu qua 2 diem ta ve 1 dg thag hoi co tat ca bn dg thg
cho n diem trong do ko co 3 diem nao thang hang . cu qua 2 diem ta ve duoc 1 duong thang . biet rang co tat ca 105 duong thang . tinh n?
n(n-1)/2
Theo đề bài n(n-1)/2=105
n(n-1)=210
n(n-1)=15.14
n(n-1)=15(15-1)
Vậy cos15 điểm
Ủng hộ mk nha
cho n diem trong do khong co 3 diem nao thang hang . Cu qua 2 diem ta ve 1 duong thang . Biet rang co tat ca 105 duong thang . tim n ?
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105 = n.(n-1):2
=n.(n-1)=105.2
=n.(n-1)=210
=n.(n-1)=15.14
vậy n = 15
ta co 105=n[n-1]chia 2
210=n[n-1]
14.15=n[n-1]
vay n=15