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Concept
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Mathematical modeling is used to generate a formula for the **number of handshakes** possible. The situation essentially asks how many sides and diagonals are in a given polygon and generates the triangle numbers: 1, 3, 6, 10, 15,

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Sample Problems
(2)

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###### Problem 1

How to determine the number of handshakes possible when you know the number of people at a party.

###### Problem 2

How to determine the number of people at a party when you know the number of handshakes possible.