Question 201844
How  many   diagonals  can be drawn in a regular 12 sided figure ?


The number of diagonals (we'll label diagonals as "d") that can be drawn in a polygon of "n" sides is given by the formula:



d = 



n(n-3)
________
2


Ok, so that fraction doesn't look very good.  I'm trying to say that the formula for diagnoals in a polygon is n(n-3) over 2.  

Let's use your 12 sided figure as our example:

12(12-3)/2   <---- this is a fraction of 12(12-3) over 2


12(9)/2  is the same as           12 x 9 over 2

108/2    is the same as           108 over 2

108/ 2 = 54

Soooooooo we can draw 54 diagonals in a 12 sided figure.  cool.