Lateral area is the surface area excluding the base and the top.
This is the sum of the areas of the three rectangles that make up its sides.
20(5+12+13)=600 square units.
Total surface area=above area plus the areas of the triangular ends. These ends have the same area=½(12)(5)=30 square units, total of 60 square units, added to the lateral area: 600+60=660 square units.
Volume=base area times height=30×20=600 cubic units.