For a Fe-0.15wt%C alloy, calculate the thickness of the ferrite half plate after four minutes of holding at 740 C. What is the degree of completion of the pro-eutectoid ferrite formation assuming that these ferrite plates are decorating the austenite grain boundaries and that the initial austenite grain size (diameter) is 200 m. Assume that the diffusion coefficient for carbon in austenite can be approximated with a pre-exponential factor of 0.076 cm2 s-1 and an activation energy of 134 kJ/mol. Further, base your calculations on a linearized Fe-C phase diagram. The equilibrium transformation temperature in pure iron is 911 C and at the eutectoid temperature of 723 C the carbon equilibrium concentration in ferrite is 0.022wt% and the eutectoid composition is 0.76wt%.