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The surface area of a cuboid formed by joining face to face 3 cubes of side x is 3 times the surface area of a cube of side x. - Mathematics

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Question

The surface area of a cuboid formed by joining face to face 3 cubes of side x is 3 times the surface area of a cube of side x.

Options

  • True

  • False

MCQ
True or False
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Solution

This statement is False.

Explanation:

Three cubes having side x are joined face-to-face, then the cuboid so formed has the same height and breadth as the cubes but its length will be thrice that of the cubes.

Hence, the length, breadth and height of the cuboid so formed are 3x, x and x, respectively.

Then, its surface area = 2(lb + bh + hl)

= 2(3x × x + x × x + x × 3x )

= 2(3x2 + x2 + 3x2)

= 2 × 7x2 

= 14x2

Now, the surface area of the cube of side x = 6 (Side)2 = 6x2.

Hence, the statement is false.

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Chapter 11: Mensuration - Exercise [Page 351]

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NCERT Exemplar Mathematics [English] Class 8
Chapter 11 Mensuration
Exercise | Q 55. | Page 351

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