If the surface area of sphere is 616 cm^2, then its radius is
If the surface area of sphere is 616 cm2, then its radius is
A) 3.5 cm
B) 7 cm
C) 14 cm
D) 21 cm
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Correct option is (B) 7 cm
Let radius of the sphere is r cm.
\(\therefore\) \(4\pi r^2=616\) \((\because\) Surface area of sphere \(=4\pi r^2)\)
\(\Rightarrow\) \(r^2=\frac{616}{4\pi}=\frac{616\times7}{4\times22}\)
\(=\frac{28\times7}4=7\times7=7^2\)
\(\Rightarrow\) r = 7
Hence, radius of sphere is 7 cm.
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