Respuesta :

ANSWER

D. 272.25 mm²

EXPLANATION

First we have to find the area of one face of one cube:

[tex]A=2.75^2=7.5625\operatorname{mm}^2[/tex]

Now we have to count how many faces of the squares are in the surface of the solid. Or a faster way is to multiply the total number of faces of the 9 cubes: 6*9=54 and subtract the number of faces that are not on the surface:

There are 18 faces of the cubes that are not on the surface of the solid. The number of faces from the 9 cubes that are on the surface of the solid is:

[tex]54-18=36[/tex]

The surface area of the solid is the area of a face of one cube multiplied by the number of faces on the surface of the solid:

[tex]SA=36\cdot A=36\cdot7.5625=272.25\operatorname{mm}^2[/tex]

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