Calculate the power exchanged by radiation by a radiator with a surface temperature of 60 C and an area of $1$ m^$2$ for each face. Assume that one face exchanges heat with the room ($($mean radiant temperature of 19 C)$)$ and one face with the wall ($($temperature of 30 C).$).$ Consider an emissivity of 0.9$\mathrm{}\mathrm{}\mathrm{}$ for the radiator and make the necessary assumption to perform the calculation.