Tren duong thang x,y lay o.Lay diem a thuoc tia ox,B thuoc tia oy sao cho OA=2cm;OB=2oa

A)Tinh do dai doan AB?

B)Goi Yla trung diem cua OB.Chung minh O la trung diem cua doan thang AI

C) Tren duong thang xy lay 100 diem diem phan biet(khac O,A,B,I).Noi 2 diem ta duoc mot doan thang.Hoi co bao nhieu duong thang tao thanh?

giup minh voi! HELP ME!!!!!

cho duong thang xy,tren do lay ba diem O ,P, Q.Hoi co bao nhieu doan thang? Ke tencac doan thang do?

cho duong thang xy va diem O nam tren duong thang xy tren tia Ox lay diem E sao cho OE=3cm.tren tia Oy lay diem G sao cho EG=6cm a)tren 3 diem O,E,G thi diem nao nam giua hai diem con lai ? vi sao b) tinh do dai doan thang OG. tu do cho biet diem O co la trung diem cua doan thang EG khong?

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?

Tren duong thang d lay 2016 diem phan biet tinh so doan thang tren hinh ve duoc tao nen tu 2016 cac diem do

cho hai duong thang a va b song song. tren duong thang a lay 10 diem phan biet, tren duong thang b lay 15 diem phan biet. hoi co the ve bao nhieu duong thang phan biet  qua 2 trong cac diem da cho ?

tinh tong 2011 cac so tu nhien le dau tien 

tren duong thang d lay 2012 diem phan biet 

tinh so doan thang tren duong thang d duoc tao thanh tu 2012 cac diem do

tren duong thang xy lay 10 diem phan biet. hoi co bao nhieu tia phan biet, co bao nhieu cap tia phan biet

cho diem O nam ngoai duong thang d. tren dung thang d lay ba diem A,B,C saocho AB=6cm;AC=2cm

a tinh BC

b gia su goc OAB=180 do;tinh goc OAC

c tren dung thang d lay them 2015 diem phan biet [khac A,B,C] hoi co bao nhieu goc co dinh O va canh di qua 2 diem thuoc dung thang d