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Around one of the cones a spiral swirls around it in a way that for each turn around the cone its height increase 1 unit (meter, foot, doesn't matter)

So if $\displaystyle \theta$ is the angle, in radians, of rotation, $\displaystyle z= \frac{\theta}{2\pi}$ and then $\displaystyle r= R(1- \frac{\theta}{2h\pi})$. Also, z= 0 when $\displaystyle \theta= 0$ and z= h when $\displaystyle \theta= 2h\pi$ Quote:

In the 2nd cone a spiral swirls around with a 30 degree angle with the horizontal.

The question is what is the lenght of each spiral and how many turns each one gives around the cone.

thanks for any help (sorry if it isn't clear, I don't have a picture)