The surface area (in m2) of a sphere of radius 7 cm is: \(\left(\text{Use } \pi=\displaystyle\frac{22}{7}\right)\)
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 0.0616
The surface area of a sphere is \(4\pi r^2\). The radius is in centimetres but the answer is wanted in square metres, and 1 m2 = 100 cm × 100 cm = 10000 cm2.
\(4\pi r^2=4\times\displaystyle\frac{22}{7}\times7\times7=616\,\mathrm{cm}^2\)
\(616\div10000=0.0616\,\mathrm{m}^2\)