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

We are learning about proofs. We drew lines between noncollinear points. Our table showed 2 points >> 1 line segment, 3 point >> 3 line segments, 4 points >> 6 line segments, 5 points >> 10 line seg, 6 points >> 15 line seg. etc.

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 2:01am
1, 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 -
**maria**, Friday, December 16, 2011 at 4:20pm
line segment 6cm and divide 5 congruent parts

- geometry -
**Anonymous**, Thursday, June 4, 2015 at 12:41pm
A circle is described by the equation x2 + y2 + 14x + 2y + 14 = 0. What are the coordinates for the center of the circle and the length of the radius?

## Answer this Question

## Related Questions

- Math - We are learning about proofs. We drew lines between noncollinear points. ...
- geometry - Trisha drew a pair of line segments starting from a vertex. Which of ...
- math - you can draw one segment to connect two points and three distinct ...
- math - you can draw one segment to connect two points and three distinct ...
- math - Ten distinct noncollinear points are chosen on a plane. a) How many line ...
- Math Geometry - A cube has 8 vertices. For each pair of distinct vertices, we ...
- geometry - which of the following is a step in constructing an inscribed square ...
- Geometry please help! - Which of these is a step in constructing an inscribed ...
- Geometry - Kelly drew four points A, B, C, and D in her notebook. A straight ...
- math - A cube has 8 vertices. For each pair of distinct vertices, we connect ...

More Related Questions