SOLUTION: if a teacher plotted points on the board in which no three are collinear and her student came up with 45 lines ,how many points were on the board?

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Question 1065895: if a teacher plotted points on the board in which no three are collinear and her student came up with 45 lines ,how many points were on the board?

Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
n= number of points
Each point can be combined with the other points to make n-1 different rays.
That would amount to m%28n-1%29 rays,
but each line would correspond to 2 rays,
so there are really n%28n-1%29%2F2=45 lines.
That is the equation to solve.
n%28n-1%29%2F2=45-->n%28n-1%29=2%2A45-->n%28n-1%29=90-->system%28highlight%28n=10%29%2Cn-1=9%29