Two cubes each of edge 12 cm are joined. The surface area of new cuboid is
Excel in Class 9th Maths with NCERT solutions and MCQ-based questions from Chapter 11: Surface Areas and Volumes. Solve exercise questions, short-answer problems and detailed explanations to grasp the concepts of calculating surface areas and volumes of solids like cubes, cuboids, cylinders, cones and spheres. These resources align with the CBSE syllabus, ensuring thorough exam preparation. Regular practice will enhance your understanding of geometric formulas and boost your confidence. Use step-by-step solutions and revision notes to simplify learning. Begin now to secure higher scores in exams.
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Explanation:
Each cube has an edge length of 12 cm. When two such cubes are joined, they form a new cuboid. The dimensions of the new cuboid are as follows:
– Length (l) = 12 + 12 = 24 cm (since the two cubes are joined along their edges),
– Breadth (b) = 12 cm (same as the edge of one cube),
– Height (h) = 12 cm (same as the edge of one cube).
The surface area of a cuboid is given by:
Surface Area = 2(lb + bh + lh).
Substitute the values of l = 24 cm, b = 12 cm, and h = 12 cm:
Surface Area = 2[(24 × 12) + (12 × 12) + (24 × 12)].
Calculate each term:
24 × 12 = 288,
12 × 12 = 144,
24 × 12 = 288.
Add these values:
288 + 144 + 288 = 720.
Multiply by 2:
Surface Area = 2 × 720 = 1440 cm².
Thus, the surface area of the new cuboid is 1440 cm², which corresponds to option b) 1440 cm².
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