You can figure out how many sides of all the cubes are unpainted (a lot of work), or you can just strip off the outside layer of cubes. The outside of the remaining block has the same area as the insides of all the deleted cubes. Its area is thus
2*(1*3 + 1*4 + 3*4) = 38
a rectangular prism 3cm x 5cm x 6cm is painted and is then cut into 1cm^3 cubes. What is the total unpainted surface area of these cubes?
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Please help! I do not understand this question.
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1 answer