The radius of a cylinder is 2 r units and height is 3 r units. Find the curved surface?
Correct answer: C. 12 πr2 sq units
- A. 18 πr2 sq units
- B. 3 πr2 sq units
- C. 12 πr2 sq units
- D. 6 πr2 sq units
Explanation
The curved surface area of a cylinder is 2πrh. With r = 2r units and h = 3r units, it becomes 2π × 2r × 3r = 12πr² square units. The likely wrong choice is 18πr² square units, which results from multiplying the dimensions incorrectly.
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Area measures the surface enclosed by two-dimensional figures, while volume measures the space occupied by three-dimensional solids. Problems use formulas for rectangles, triangles, circles, prisms, cylinders, cones, spheres, and composite figures, including unit conversion and the distinction between surface area, lateral area, and volume.
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