In today's Science section....
How many triangles are formed by six intersecting lines? Given that no two lines are parallel, and there are no points where more than two lines intersect.
Thread: Math Puzzle in The NYTimes....
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08272019 09:46 PM

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08282019 03:13 PMFor each of the six lines, every one of the five (nonparallel) lines crosses exactly once. For each of those pair of lines each of the four remaining lines must cross to form a triangle. That defines 6×5×4=120 line combinations that form triangles, but does not take into account that abc, bac, cba, etc are the same triangle. There are 3×2×1=6 such ways to describe each triangle, so there are 120/6=20 unique triangles. There is a fancy mathematical way to write this, but I forget how.

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08282019 03:47 PMit's actually the point of a pin and the answer is 8.6766×10exp49
https://improbable.com/airchives/pap...angels73.htm

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08292019 03:55 PM20 is the answer....

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08302019 01:53 PMIt depends on the angles between the angels.