A polygon has 1325 diagonals. How many vertices does it have?

The formula for number of diagonals in a polygon is
n(n-3)/2 where n is the number of sides.
Since here, we are given the number of diagonals,
n(n-3)/2=1325
n*n - 3n = 2650
n*n - 3n - 2650 = 0,
we get n as 53. Hence the number of sides is 53, and since the number of sides = number of vertices, the number of vertices is 53.
Thanks

Posted by shawn on 2004-02-15 22:19:54