Correct option is: A) 6.6 cm
Given that the surface area of sphere is S = 550 \(cm^2\).
\(\therefore\) \(4 \pi r^2 = 550\)
\(\Rightarrow\) \(r^2 = \frac {550}{4 \pi} = \frac {550 \times 7}{4 \times 22} = \frac {25 \times 7}{4} = (\frac 52)^2 \times 7\)
\(\Rightarrow\) r = \(\frac 52 \sqrt7 \, cm = 2.5 \times 2.64 \, cm = 6.6 \, cm\)
Hence, radius of the sphere is 6.6 cm.
