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Basic Mathematics
QUESTION #7944
Question 1
The radius of a sphere is increased by 10%. By what percentage does the surface area increase?
Correct Answer Explanation
Surface area of a sphere \(= 4\pi r^2\).
New radius \(= 1.1r\), so new surface area \(= 4\pi(1.1r)^2 = 4\pi \times 1.21r^2\).
Increase \(= 21\%\).
New radius \(= 1.1r\), so new surface area \(= 4\pi(1.1r)^2 = 4\pi \times 1.21r^2\).
Increase \(= 21\%\).
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