Question

Calculate the surface area of a sphere whose radius is $21cm$.

• A. $5544{cm}^2$
• B. $6622{cm}^2$
• C. $7733{cm}^2$
• D. $4455{cm}^2$

Answer 1

Answer: (A)

$5544{cm}^2$

Given, radius $r=21cm$.

We know, the surface area of a sphere of radius $r$ $=4\pi r^2$

$=4\times \frac{22}{7}\times 21\times 21$

$=5544{cm}^2$.

Therefore, option $A$ is correct.