Question

How many cubic meters of earth must be dug out to sink a well 16m in depth and 7m in diameter?

Answer 1

Radius = Diameter/2= 7/2m

Height= 16m

Volume of cylinder= πr^2h=22/7*7/2*7/2*16=22/7*49/4*16=616m^2

Answer 2

$Radius = \frac{1}{2} \times Diameter$

$= \frac{7}{2}m$

$Height = 16 m$

$\red{Volume \: of \: cylinder = \pi {r}^{2}h}$

$\blue{ \frac{22}{7} \times \frac{7}{2 \times \frac{7}{2} } \times 16}$

$\purple{616 {m}^{2} }$