How many cubic metres of earth must be dug-out to sink a well 21 m deep and 6 mdiameter?
Given,
Height of cylinder = 21 m
Diameter of well = 6 m
radius of well = 
so,
Amount of earth can be dug out from this well = 
19
How many cubic metres of earth must be dug-out to sink a well 21 m deep and 6 mdiameter?
Given,
Height of cylinder = 21 m
Diameter of well = 6 m
radius of well =
so,
Amount of earth can be dug out from this well =