how many straight lines can be formed from 8 non collinear points on the X-Y plane?

Question

how many  straight lines can be formed from 8 non collinear points on the  X-Y plane?

anonymous · Answer

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I know this only shows 7 lines but you can keep going around and do it for each of the 8 points

so I believe it is 7 multiplied by 8

anonymous · Answer

wait nope that's wrong
because when you get to the 2nd point you're only making 6 lines

anonymous · Answer

so it'll be 7!
7*6*5*4*3*2*1

dan815 · Answer

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dan815 · Answer

a connection exists between 2 points

dan815 · Answer

how many ways can we pick 2 points
that is 8*7 ways 
but order will matter in this case so to disregard order you divide by 2! or 2

anonymous · Answer

oh snaps you're right dan =O
sorry about that suman

amoodarya · Answer

|dw:1388494530830:dw|dan815 was right