Question:
The surface area of a cuboid formed by joining two cubes of side a face to face is __________.
Solution:
10a2
Explanation:
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