The heat exchange in a wall depends on distance using the Fourier rule. can be calculated. q=-kA dt/dx Where T is the wall temperature, A is the surface area where heat is lost, and k is indicates thermal conductivity. In the table below, the distance from the surface depending on the temperature change. k=0.039 kcal/m.h.o C and For values ​​given as A=1.5 m2, x=0; The heat at x=0.2 and x=0.25 m calculate. x (m) 0 0.1 0.2 0.3 0.4 T (o C) 100 70 40 25 20