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    Question

    Two identical cubes are joined together to form a

    cuboid. If each cube has a total surface area of 54 cm², what is the total surface area of the resulting cuboid?
    A 30 cm² Correct Answer Incorrect Answer
    B 90 cm² Correct Answer Incorrect Answer
    C 43 cm² Correct Answer Incorrect Answer
    D 35 cm² Correct Answer Incorrect Answer

    Solution

    ATQ,

    Let the length of each edge of the cube = ‘a’ cm

    So, 6 × a² = 54

    So, a² = 9

    Or, a = 3

    So, length of the cuboid = 2 × a = 2 × 3 = 6 cm

    Width of the cuboid = a = 3 cm

    And, height of the cuboid = a = 3 cm

    Desired area = 2 × (3 × 3 + 3 × 6 + 3 × 6) = 2 × 45 = 90 cm²

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