Q3 of 32 Page 267

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


Given that, height of cylindrical well(H) is 20 m and diameter(d) is 7 m. And length(l) and breadth(b) of rectangular platform are 22m and 14 m respectively.


Now, let the height of platform be h.


⇒ radius of cylinder(r)


⇒ vol. Of well = vol. of platform


⇒ πr2H = lbh




⇒ h = 2.5 cm


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