A triangular number is the number of dots in an equilateral triangle with dots uniformly filled. For example, the three dots may form a triangle and hence 3 is a triangular number. The n-th

triangular number is the number of dots of a triangle on the side of the n points. Equivalently, a triangular number is the addition of the first n positive integers from 1 to n.

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The handshake problem:“If a group of n people greet each other, the total number of handsheaks will be triangular number”.

To make a fully connected network of PC. The nodes of the network are connected to more than oneother node in the network with a point-to-point linkThis is the triangular number of the internet nodes.

[1] http://en.wikipedia.org/wiki/Triangular_number [2] http://www.shyamsundergupta.com/triangle.htm [3] https://mathblag.wordpress.com/2012/06/23/a-product-rule-for-triangular-numbers/ [4] http://unurthed.com/2007/11/21/polygonal-numbers-and-a-slice-of-pie/ [5] http://en.wikipedia.org/wiki/Network_topology#Mesh