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Question
Two identical cubes each of volume 64 cm3 are joined together end to end. What is the surface area of the resulting cuboid?
Solution
Let the side of one cube = a
Surfaces area of resulting cuboid = 2(Total surface area of a cube) – 2(area of single surface)
We know that,
Total surface area of cube = 6a2, where a = side of cube
⇒ Surfaces area of resulting cuboid = 2(6a2) – 2(a2) = 10a2
Also,
According to the question,
Volume of cube = 64 cm3
Volume of cube = a3
64 = a3
a = 4 cm
Therefore, surface area of resulting cuboid = 10a2 = 10(4)2 = 160 cm2
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Assertion (A)
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