Mensuration-3

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A 20 m deep well with a diameter 14 m was dug up and the earth from the digging was
spread evenly to form a platform 22 m x 14 m. Calculate the height of the platform.

Solution: For cylinder well, Radius = 14/2 = 7 m

Depth = 20 m

Volume = π r² h = π x 7² x 20 = 980 π m³

Area of the platform = 22 x 14 = 308 m²

Let the height of the platform be h m.

Then volume = 308 h m³

According to the sum 308 h = 980 π

h = 980 π / 308 = 980 /308 x 22/7 = 10

Therefore, the height of the platform is 10 m.