Q. 64.0( 9 Votes )

# The height of a cone is 20 cm. A small cone is cut off from the top by a plane parallel to the base. If its volume be 1/125 of the volume of the original cone, determine at what height above the base the section is made.

Answer :

Height of the cone = 20cm

Let the small cone was cut at the height x from the top then height of the small cone = x cm

From cones ABC and AEF,

(h’, r’ and h’’, r’’ are heights and radius of larger and smaller cones resp.)

-------(i)

Given: Volume of the small cone = × volume of the large cone

And Volume of a cone =

⇒ x = 4cm

Height at which section is made = 20 – 4 = 16cm

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