mensuration

Asked by  | 12th Mar, 2009, 09:41: AM

Expert Answer:

If the cone of height d is cut by a plane at a height of d/3 then the height of upper cone will be 2/3 d

Triangles ODF and OAC are similar so

r/R = (2/3d)/d

r = 2/3 R

Now Compute the volume of frustum by taking radii R and 2/3 R and height d/3 = 1/3 ΠR2d/3[1+2/3+4/9]

and Volume of cone with radius R and height d = 1/3 ΠR2d

 

So the Volume of frustum/volume of cone = [1+2/3+4/9]X1/3

Taking the % age we have 1900/27 = 70.37%

Answered by  | 13th Mar, 2009, 11:24: AM

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