# Quick math question

1. Dec 4, 2007

### get_rekd

d=n^2 - 3n / 2

where d = number of diagonals
and n = the number of sides of the polygon.

A polygon has 119 diagonals, how many sides does it have?

119 = n^2 - 3n / 2

sorry this isn't physics related

2. Dec 5, 2007

### Bill Foster

An n-sided polygon has this many diagonals:

$$\frac{n(n-3)}{2}$$

Solve for $$n$$.

3. Dec 5, 2007