We are given a rectangular piece of tin with an area of: Area of Tin Piece = Length * Width Area of Tin Piece = $12 \times 8 = 96$ cm² For a closed cube, the surface area is given by the formula:

Surface Area of Cube = $6 \times (\text{Side length})^2$ Let the side of the cube be x. So, the total surface area of the cube is:

Surface Area of Cube = $6 \times x^2$ Since the area of the tin piece is used to cover the surface area of the cube, we equate the two: $6 \times x^2 = 96$

Solving for x: $x^2 = 96 / 6$ $x^2 = 16$ $x = \sqrt{16}$ $x = 4$ cm

Thus, the side of the cube is 4 cm.