A farmer built a fence around his 17 cows,in a square shaped region.He used 27 fence poles on each side of the square. How many poles did he need altogether?

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