The radius of the circle=4√2 feet.

The diameter of the circle=8√2feet.

The diameter of the circle=The hypotenuse of a triangle whose other sides are identical.

According to pythagoras theory

2×(side of square)^{2}=(hypotenuse)^{2}

Side of square =√{(8√2)^{}^{}^{2}/2}=8feet.

The perimeter of garden =perimeter of square=4×side of square=32 feet.