Final answer:
Chris needs 12 feet of fencing material.
Step-by-step explanation:
To calculate the amount of fencing material Chris needs, we need to find the perimeter of the square garden. Since all sides of a square are equal, we can simply multiply the length of one side by 4. In this case, the garden measures 3 feet on each side, so the perimeter is 3 feet x 4 = 12 feet.