The surface area of a cuboid formed


The surface area of a cuboid formed by joining two cubes of side a face to face is __________.




Let “a” be the side of two cubes.

When the two cubes are joined face to face, the figure obtained should be a cuboid having the same breadth and height. As the combined cube has a length twice of the length of a cube.

It means that l = 2a, b = a and h = a

Hence, the total surface area of cuboid = 2(lb + bh + hl)

= 2(2a × a + a × a + a × 2a)

Simplify the above expression, we get

= 2[2a2 + a2 + 2a2]

= 10a2

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