For this case, what you should do is calculate the surface area of the figure. We have then: Triangles: A1 = (1/2) * (7) * (12) A1 = 42 in ^ 2 Rectangles: A2 = (1) * (12.5) A2 = 12.5 in ^ 2 A3 = (1) * (7) A3 = 7 in ^ 2 Finally, the total surface area is: A = 2A1 + 2A2 + A3 Substituting values: A = 2 (42) + 2 (12.5) + (7) A = 84 + 25 + 7 A = 116 in ^ 2 Answer: the amount of cardboard needed to make a box for a single slice of pizza is: A = 116 in ^ 2