To solve this problem, the user needs to know the formula to calculate the perimeter of a square and the total number of poles required to build a fence.
The formula to calculate the perimeter of a square is P = 4s where P represents the perimeter and s represents the length of one side of the square.
To build a fence around a square-shaped region, we need two poles per unit of length. Therefore, the total number of poles required is twice the perimeter of the square.
Let s be the length of one side of the square. From the question, we know that the farmer used 27 fence poles on each side of the square. Therefore,
$2s + 1 = 27$
Solving for s, we get
$s = 13$
Substituting s in the formula for the perimeter of a square, we get
$P = 4s = 4\times13=52$
Therefore, the total number of poles required is
$2P=2\times52=104$
Hence, the answer is:
The Answer is: D. 104