Cone help

[higgles]

Hello,

I need some help! I am trying to make a cone for which the diameter needs to be 47mm and height 100mm. I have tried hundreds of sizes of circles but it's either not the right size or not a cone. Can anyone advise before I go loopy

Thank you!

[wombat]

you might be able to make sense of this formula:
http://jwilson.coe.uga.edu/emt725/Ca.../Solution.html

or this:
http://mathcentral.uregina.ca/QQ/dat...3/tracie1.html

[DJG]

Deleted

[Jimjams]

There is a calculator here to help you.
I typed in the radius of the bottom part (47mm/2) and the height (100mm) and it reveals that the radius of the circle that you need is 102.7mm (slant height)

[Nerlly]

Blimey! I found that as well, Pam, but I didn't want to look too closely in case it bit me, lol.

Higgles, this is off the top of my head and there is probably a deep flaw in it somewhere, but what happens if you try this:

Get a big circle cut across the radius and roll it in to a cone but don't glue anything yet. Mark the height you want on something upright (like the wall, lol) so that you can measure the cone against it (easier, I would have thought, than trying to measure the height of a sloping side). Cut your cone down so that it's the right height, then roll it tighter/looser until it's the right diameter. Mark where the edges meet and then when you open it up you've got a template, or you can just use the same circle of paper, cut down to the right size.

Hope that works.....

[Nerlly]

There is a calculator here to help you.
I typed in the radius of the bottom part (47mm/2) and the height (100mm) and it reveals that the diameter of the circle that you need is 102.7mm (slant height)

Or, of course, you could do that, lol!

[Jimjams]

Ooops - typed diameter instead of radius - you need a radius of 102.7mm

[Jimjams]

In fact just found the calculator I used a while back when making origami Christmas trees - it's even better as it also tells you how much of your circle (*S* angle) you need:

A sector of 82.4 degrees plus a little extra for glueing together - so I reckon you could make 3 or 4 cones from the circle.