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
