The area of a square is found by S^2 where S is the length of a side.
The garden and path are 11 feet wide, so the total area for both is 11^2 = 121 square feet.
The length of a side of just the garden would be 11 - 4 ( 2 feet of path on both sides) = 7 feet
The area of the garden would be 7^2 = 49 square feet.
the area of the path would be the total area minus the area of the garden: 121-49 = 72 square feet.