Area of a cone

[glass]

I am having a real problem finding the surface area of a cone, and since I know there are some very smart people here at ENworld, I thought I'd try my luck.

Two web searches (one by me and another by a coleage) have turned up two different forlmae, neither of which seems to be right.

So doe anyone know a formula for the surface area of a cone?


glass.

 

[GeorgeFields]

Check this out.

http://www.webcalc.net/calc/0040.php

 

[Jdvn1]

... Which two equations did you find?

 

[glass]

... Which two equations did you find?

One site claimed it was (1/3 x pi x radius squared x height), and another had a horrendously complicated formula with multiple trig functions. Both had the slight problem of tending to produce results that were less than the area of a flat circle!


glass.

 

[glass]

Check this out.

http://www.webcalc.net/calc/0040.php

Thanks. I was actually coming back to say that we've come up with better formula ourselves, but that site comes up with the same result, which is reassuring!


glass.

 

[Staffan]

If you're wondering about stuff, check the wikipedia. In this case, http://en.wikipedia.org/wiki/Cone_(solid)