Question

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

Answer 1

Surface area of a sphere $=154c{m}^2$
Since, surface area of sphere $=4\pi r^2$
Therefore, Radius $=\sqrt{\frac{Surfacearea}{4\pi }}=\sqrt{\frac{154\times 7}{4\times 22}}cm$
$=\sqrt{\frac{49}{4}}=\frac{7}{2}cm=3.5cm$