The image as a base of 12 x 10 =120 two triangular size with a total surface area of 1/2 x 5 x 12 x 2 = 60, a back side surface area of 10 x 5 = 50 and a top surface area of 13 x 10 = 130. Add it all together and you have 120 + 60 + 50 + 130 for a total surface area of 360 cm