Answers:
- Surface Area = 276 square inches
- Volume = 280 cubic inches
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Explanation:
It might help to draw this out on paper, cut the figure out, and fold along the lines to form a 3D box.
Check out the diagram below. In steps 1 through 4, we go from a flat 2D net to a 3D box. Steps 2 and 3 basically are just intermediate steps to show the folding process. If this was done with an animation, it might look better (you'll have to use your imagination a bit).
The letters A through F in red should help us see how the flat 2D figure connects to the 3D one. For me, it helps to picture a room. The floor is face B, the ceiling is E, and so on.
Anyways, once we get the 3D box, it has the following dimensions:
- L = length = 10 inches
- W = width = 7 inches
- H = height = 4 inches
The order of length, width and height doesn't matter.
Once we know these values, we can plug them into the formulas below
where SA and V are the surface area and volume respectively.
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So,
SA = 2(LW+LH+WH)
SA = 2(10*7 + 10*4 + 7*4)
SA = 2*(70+40+28)
SA = 2*138
SA = 276 square inches is the surface area
and,
V = L*W*H
V = 10*7*4
V = 280 cubic inches is the volume
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As an alternative way to get the surface area, you can compute the areas of rectangles A through F, and then add up those areas to get the overall surface area.
It's a bit interesting how the surface area and volume are almost nearly the same number. Though that could be a coincidence.