Final answer:
To find the minimum amount of fencing needed for a rectangular garden, we need to calculate the perimeter of the garden. However, without the dimensions of the garden or the ratio of length to width, we cannot determine the minimum amount of fencing needed.
Step-by-step explanation:
To determine the minimum amount of fencing needed for a rectangular garden, we need to find the perimeter of the garden. The formula to calculate the perimeter of a rectangle is Perimeter = 2 * (length + width). Since the problem states that the garden is exactly 81 meters, we can set up the equation as 2 * (length + width) = 81. However, we don't have enough information to solve for the exact dimensions of the garden or the ratio of length to width, so we cannot determine the minimum amount of fencing needed.