perplexus.info :: Geometry : How Many Triangles...

How Many Triangles... (Posted on 2004-08-15)

... (maximum) can be formed with n straight lines?

See The Solution Submitted by SilverKnight

Rating: 2.2857 (7 votes)

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Puzzle Thoughts

Comment 9 of 9 |

Thus, this problem is equivalent to the question: "In how many different ways can n lines be taken three at a time?"

The answer is comb(n,3) = n(n-1)(n-2)/3! = n(n-1)(n-2)/6

Posted by K Sengupta on 2023-03-16 02:20:15

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