Question

Find the radius of a sphere whose surface area is $154{cm}^2.$

• A. $3.5$ cm
• B. $4.5$ cm
• C. $4$ cm
• D. $3$ cm

Answer 1

The correct option is A $3.5$ cm

Given, surface area of sphere $=154c{m}^2$

Surface area of a sphere of radius '$r$' $=4\pi r^2=154$

$\Rightarrow 4\times \frac{22}{7}\times r^2=154{cm}^2$

$\Rightarrow r^2=\frac{49}{4}$

$\Rightarrow r=\frac{7}{2}=3.5cm$.

Therefore, option $A$ is correct.