Originally Posted by

**iva** Maybe this is a really stupid question, but its bugging me and seems very stupid

I understand that area of a circle is pi r^2 and area of a cone(excluding the base) is pi r s where s is the distance from the top of the cone to its base, and i understand how to get there.

But i was just thinking if that code was a retractable metal object made of very fine rings you could flatten it into a circle that should surely have the same area. but its only the case obviously if r = s then the areas are equal ie

pi r^2 = pi r s = pi r^2

Surely even by integration (not sure quite how) this would be the case? where you would integrate thin concentric rings...

Hope this isn't the dumbest question ever asked