Question 891676
The volume of a cone having an inclined axis at an angle of 60 degrees with the
base is equal to 1884.96 cu.m., find the length of the axis of the cone, if the
radius at the base 10m.<pre>

{{{drawing(400,8200/23,-11,12,-1.5,19,

green(triangle(-10,0,10,0,0,18),line(0,0,0,18,10,0)),

arc(0,0,20,3),locate(2,2.5,"60°"),red(locate(5.3,10.5,A)),
locate(4,0,10m),green(locate(.1,9,h)),red(locate(10.5,9,h)),
red(triangle(-10,0,10,0,10.39230585,18),triangle(0,0,-10,0,10.39230585,18))

)}}} 

Let A be the axis of the red cone. The green cone has the same 
vertical height as the red slanted cone and has the same volume.

The volume of the green cone is

{{{V=expr(1/3)pi*r^2h}}}

{{{1884.96=expr(1/3)pi(10)^2h}}}

{{{1884.96/(expr(1/3)pi(10)^2)=h}}}

{{{18.00004209=h}}}

We'll just round that to 18m.

{{{h/A=sin("60°")}}}

{{{18=Asin("60°")}}}

{{{18/sin("60°")=A}}}

{{{20.78460969=A}}}

So the axis is about 20.8 m

Edwin</pre>