A furnace is hsaped like a long equilateral-triangular duct where the width of each side is 2 m. Heat is supplied from the base surface, whose emissivity is = 0.8 at a rate of 800 W/mm^2 while the side surface whose emissivities are 0.5, are maintained at 500K. Neglecting the end effects determine the temperature of the base surface. can you treat this geometry as a two surface.