Question

The surface area of a sphere is $616{cm}^2$. Find the diameter of the sphere (in $cm$).

Answer 1

Surface area of sphere$=4\pi r^2$.
According to the statement,
$4\pi r^2=616$
$⟹$ $4\times \frac{22}{7}\times r^2=616$
$⟹$ $r^2=\frac{\stackrel{7}{616}\times 7}{4\times 22}$
$⟹$ $r^2=7\times 7$
$⟹$ $r^2=49$
$⟹$ $r=7cm$.
$\therefore$ Diameter of the sphere$=2r$ $=2\times 7$ $=14cm$.