SOLUTION: ron was doodling in his notebook and noticed the following: 3 segments can be drawn between 3 points, 6 segments can be drawn between 4 points, and 10 segments can be drawn between

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: ron was doodling in his notebook and noticed the following: 3 segments can be drawn between 3 points, 6 segments can be drawn between 4 points, and 10 segments can be drawn between      Log On


   

Question 256439: ron was doodling in his notebook and noticed the following: 3 segments can be drawn between 3 points, 6 segments can be drawn between 4 points, and 10 segments can be drawn between 5 points.
a. find an equation giving the number of segments "y" as a function of the number of points "x".
b. according o this formula howmany segments can be drawn between 70 points.
c. how many points are needed to draw 45 segments between them.
Answer by drk(1908) About Me  (Show Source):
You can put this solution on YOUR website!
Here the pattern is 1,3,6,10, . . .
The formula is
Y+=+%28x%2A%28x%2B1%29%29%2F2
where x is the number of points
--
If x = 70, then
Y+=+%2870%2A%2870%2B1%29%29%2F2 = 2485 segments
--
45+=+%28x%2A%28x%2B1%29%29%2F2
90+=+x%2A%28x%2B1%29
x = 9, x+1 = 10.
We need 9 points for 45 segments