Project Euler Problem 25 Solution

Important concepts. Binet's Formula for finding the nth fibonacci number
Useful link:http://www.geekality.net/2009/11/06/project-euler-problem-25/

Code is just one line: (int) Math.Ceiling((1000 + Math.Log10(5) / 2 - 1) / Math.Log10(1.61803))

1.61803 is the approximate equivalent of golden ratio ((1+sqrt(5))2)