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# I'm very confused...

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Ten points are chosen on a circle. A line segment is drawn between every pair of chosen points. How many line segments are drawn?

:)

Apr 26, 2020

#1
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10*9 = 90 = number of line segments drawn

Apr 26, 2020
#2
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that doesn't seem to be right... but thanks for helping :)

lokiisnotdead  Apr 26, 2020
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Guest has unfortunately counted every segment twice O_O

AnExtremelyLongName  Apr 27, 2020
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9+8+7+6+5+4+3+2+1 = 45      I think.

Apr 26, 2020
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wow! that's right! thanks Melody!

lokiisnotdead  Apr 26, 2020
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The solution it gives me is:

There are \({10 \choose 2} =45\) ways to choose two of the points to connect with a segment, so there are \(\boxed{45}\) segments drawn.

Apr 26, 2020
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I think I like Melody's method the best because it is a good way to visualize the solution. The official solution is the best if you are familiar with these types of problems.

AnExtremelyLongName  Apr 27, 2020