A cube of side 6 cm is painted on all its faces and then cut into smaller cubes each of side 2 cm. Find the number of cubes which have exactly two faces painted.
12
Cutting a 6 cm cube into 2 cm cubes gives \(\frac{6}{2} = 3\) divisions per edge, so a total of \(3\times3\times3 = 27\) small cubes.
Small cubes with exactly two painted faces lie along the edges of the big cube, excluding the corner cubes. Each edge of the big cube has \((3-2) = 1\) such cube.
A cube has 12 edges, so the number of small cubes with exactly two faces painted is \(12\times1 = 12\).
There are 12 such small cubes.
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- The base diameter of a cylinder is 21 cm and the height is 28 cm, then:
(A) Radius of cylinder = 10.5 cm
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(C) Curved Surface Area = 1848 cm²
(D) Total surface area = 2541 cm²
Which of the following is/ are correct?
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A solid cylinder has a radius of 7 cm and height of 10 cm. Find its total surface area. (Use \(\pi = \dfrac{22}{7}\))
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- The numerical values of perimeter and area of a square are equal. The length of the side of the square is :
