Can someone please give me a step by step on this problem (surface area and volume)

Surface area would be adding up all the areas for all the sides which would be (16x16)+ (1/2 x16x17)+ (1/2 x16x17)+ (1/2 x16x17)+ (1/2 x16x17)= 800
Area
(16x16) x (15/3)= 1280