chain a sheep to a round silo, what is the area it can graze ?
while trying to solve this I came through a series of answers, and if we give same values in their solution I'm getting entirely different values . Help me to find suitable solution.

http://www.ralphhuijgen.com/2013/06/the-meanest-puzzle-for-your-friends-or-teacher-a-sheep-and-his-g razing-area/#comment-106

http://mathworld.wolfram.com/GoatProblem.html

http://mathforum.org/library/drmath/view/53763.html

these are the links gives its solution, which I came through. If you know some other methods kindly share it.

Question

chain a sheep to a round silo, what is the area it can graze ? 
while trying to solve this I came through a series of answers, and if we give same values in their solution I'm getting entirely different values . Help me to find suitable solution. 

http://www.ralphhuijgen.com/2013/06/the-meanest-puzzle-for-your-friends-or-teacher-a-sheep-and-his-g razing-area/#comment-106 

http://mathworld.wolfram.com/GoatProblem.html 

http://mathforum.org/library/drmath/view/53763.html 

these are the links gives its solution, which I came through. If you know some other methods kindly share it.