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The surface area of a sphere of radius r equals:
Answer & Solution
Correct answer: A.
1. The surface area is the total outer area covering the sphere.
2. The textbook derives this by inscribing the sphere in a cylinder and showing the curved surfaces have equal area.
3. The covering cylinder has height 2r and curved area 2πr × 2r = 4πr².
4. So the sphere's surface area is also 4πr².
5. (4/3)πr³ is the volume of the sphere, not the surface area.
_Source: SCERT Kerala Std X Mathematics Part-2, Chapter 8-9 (pp 200-219, 2019 ed.)._
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