A triangular fin of stainless steel (18% Cr, 8% Ni) is attached to a plane wall maintained

Question:

A triangular fin of stainless steel (18% Cr, 8% Ni) is attached to a plane wall maintained at 460ºC. The fin thickness is 6.4 mm, and the length is 2.5 cm. The environment is at 93ºC, and the convection heat-transfer coefficient is 28 W/m2 ∙ ºC. Calculate the heat lost from the fin.