In an annealing process, a 50-mm-thick stainless steel plate (\rho = 8238 kg/m^3, Cp = 468 J/kg·c, k = 13.4 W/m·c, and \alpha = 3.48 x 10⁻⁶ m^2/s) and an initial temperature of 230 \deg C is reheated in a furnace. The uniform ambient temperature inside the furnace is 1000 \deg C with a convection heat transfer coefficient of 215 W/m^2·K. If it is left for 200 seconds to cool, determine the temperature at the center and the extremities of the plate.