A closed box is filled with dry ice at a temperature of -78.7 C, while the outside temperature is 17.2 C. The box is cubical, measuring 0.255 m on a side, and the thickness of the walls is 4.08 x 10 2 m. In one day, 3.27 x 10 J of heat is conducted through the six walls. Find the thermal conductivity of the material from which the box is made. Number i Units