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January 30, 2015

January 30, 2015

Posted by **Zack** on Wednesday, October 8, 2008 at 1:18am.

Write an expression in terms of n for the number of line segments that can be drawn between n points.

Please help.

- geometry -
**drwls**, Wednesday, October 8, 2008 at 2:01am1, 3, 6, 10,.. is the series

N*(N-1)/2

where N is the number of points.

These are sometimes refered to as triangle numbers. (This of stacking pop cans in a triangle with rows of 1, 2, 3, 4 etc.)

See http://en.wikipedia.org/wiki/Triangular_numbers

- geometry -
**Zack**, Wednesday, October 8, 2008 at 2:07amThank you very much. I could explain it (I thought) but couldn't express it in math terms. Thanks again

- geometry -
- geometry -
**maria**, Friday, December 16, 2011 at 4:20pmline segment 6cm and divide 5 congruent parts

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