To find the length of each side of the square, we need to divide the total length of the wire by the number of sides in each square.
Since there are 4 squares, the total number of sides is 4 x 4 = 16.
Therefore, the length of each side of the square is:
240 cm ÷ 16 = 15 cm
Hence, the length of each side of the square is 15 cm.