A40m deep well with radius 3.5m is dug and the earth taken out is evenly spread to form aplateform of dimension 28m by 22m.find the height of the platform.

Volume of well

= π r^2 h
= π(3.5)^2 (40)
= 490π cubic metres

let the height of the plateform be h
28(22)h = 490π
h = 490π/616
= 35π/44 metres or appr 2.5 m

Answer

thanks so much

28*22*h=490π h=2.5m

V of the well =πr^2h= π(3.5)^2×40

=490π m^3

Let the height €
€×22×28 = 490π
€=490π\616 m^3
€=35π\44
€= ~2.5m

Correct, the height of the platform is approximately 2.5 meters.

A.A