# Volume of a Right Circular Cylinder

Volume of a cylinder = area of the base Ã— heightÂ

Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â = area of the circle Ã— height

Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â = pr^{2}h cu. units

Â

In a field 40 m Ã— 25 m, a well of 7 diameter is dug and earth taken out is evenly spread in the remaining area of the field to raise the level by 50 cm, find the depth of the well.

Â

Area of a rectangular field

Â Â Â Â Â Â Â Â = l Ã— b

Â Â Â Â Â Â Â Â Â = 40 Ã— 25

Â Â Â Â Â Â Â Â =1000 sq. m

Area of the mouth of the well (circle)

Â = pr^{2}= Ã— Ã— Â = 38.5 m^{2}

Area of the remaining field = 1000 - 38.5 = 961.5 m^{2}

Volume of the earth = Volume of the well = pr^{2}h

Ãž Area of the remaining field Ã— rise in the level of theÂ field = pr^{2}h

ÃžÂ 961.5 Ã— = Ã— Ã— Â Ã— h (h = depth of the well)

ÃžÂ h = 12.487 m.

Â

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