Question

The surface area of a sphere of radius 21 cm is
(a) 2772 cm²
(b) 1386 cm²
(c) 4158 cm²
(d) 5544 cm²

Answer 1

(d) 5544 cm²

Surface area of sphere = $4\mathrm{\pi }{r}^2$
= $$\begin{gathered} 4\times \frac{22}{7}\times 21\times 21 \\ =5544{\mathrm{cm}}^2 \end{gathered}$$