SOLUTION: how many distinct lines can be drawn through 15 point no 3 of with are in the same straight line?

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Question 480484: how many distinct lines can be drawn through 15 point no 3 of with are in the same straight line?
Answer by Edwin McCravy(20055) About Me  (Show Source):
You can put this solution on YOUR website!
If the 15 points are labeled A,B,C,D,E,F,G,H,I,J,K,L,M,N,O then since
two points determine a line, and since order doesn't matter (since AB
and BA determine the same line), the answer is "15 things choose 2" which
is called "the number of combinations of 15 things taken 2 at a time",
which is sometimes written 15C2, or C(15,2) or 15C2 or %28matrix%282%2C1%2C15%2C2%29%29.
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It is calculated as 

Edwin