A 20 m deep well with diameter 7 m is dug and the earth from digging is evenly spread out to form a platform 22 m by 14 m. Find the height of the platform.

Explanation

Diameter = 7 m
so, radius = 3.5 m
Earth dug out from (cylindrical) well`=pixxrxxrxxh`
`=22/7 xx3.5xx3.5xx20`
`=770m^3`
volume of cuboid = `lxxbxxh`
`770=22xx14xxh`
so, height `=770/22 xx14`
`= 2.5m`