The angle

is in Quadrant 1 and cos of an angle in quadrant 1 is always positive
The graph would open at the down at the bottom
We know that area of the square is 141 square feet. Therefore, we can figure out the dimension of square using formula for area as shown below:

We know that fencing is used along the sides of the square. Therefore, amount of fencing required will be equal to perimeter of square.
Hence, we can write:


Upon rounding to nearest foot, we get the amount of fencing required as 48 feet.
It would be either C or A, sorry I cant help anymore than that