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Find an expression, in terms of h, for the height of the frustum.

Find an expression, in terms of h, for the height of the frustum.-example-1
User Newts
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1 Answer

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Answer:

height = 2/5h

Explanation:

You want the height of a frustum if the volume of the frustum is 98/125 times the volume of the original cone, which was of height h.

Removed part

Let h' represent the height of the part of the cone that is removed to leave the frustum. Then its volume (v') is ...

v' = (volume of large cone)(1 - 98/125) = v·(27/125)

The scale factor between h' and h is ...

(h'/h)³ = v'/v = 27/125

h'/h = ∛(27/125) = 3/5

Frustum

The height of the frustum in terms of the height of the original cone is ...

frustum height = (height of large cone) - (height of small cone)

frustum height = h - (3/5)h

frustum height = 2/5h

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User TechTravelThink
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