An aluminum triangular fin is used to cool an electronic package which dissipates 7.5W. The fin is mounted on one of the package's rectangular surfaces. The base of the fin measures 2 cm x 10 cm and its length is 12 cm. The fin is cooled by convection with a heat transfer coefficient 9.2 W/m/K and the ambient temperature is 18 C. Determine the surface temperature of the package.