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How does the surface area of a sphere change when the radius is tripled?A. The surface area doesn't changeB. The surface area is increased by 9C. The surface area is doubledD. The surface area is multiplied by 9

User Ruchita
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8.8k points

1 Answer

4 votes

We must have in mind the surface of a sphere that is given by


S_a=4\pi r^2

When the radius of the sphere triples, the new radius becomes r1=3r. So, the new surface area of a sphere is


S_(a1)=4\pi(3r)^2=9(4\pi r^2)=36\pi r^2

As we can see, the surface area is multiplied by 9. The correct answer is D.

User IMSoP
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7.8k points
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