An octahedron is a closed 3-d shape with 8 polygonal faces. There are 257 topologically different convex octahedra. Several of these may be considered as octahedron cone and the answer depends on which particular shape you have in mind.
Infinite
14
If it is a right circular cone, it has an infinite number of planes of symmetry. If it is an oblique circular cone, it has one plane of symmetry.
One.
A cone has infinitely many lines of symmetry. This is because any line passing through the apex (point) of the cone will divide it into two symmetrical halves. The cone's circular base also serves as a line of symmetry when paired with a corresponding line passing through the apex.
An octahedron has 7 perpendicular lines.
It need not have any.
A triangle has only one line of symmetry but who ever says there are more than two is a idiot * * * * * A triangle, in general has NO line of symmetry, so who ever (or whoever) says there is one is and acts smart about it is a bigger idiot! That is even more so when the question is about a cone and not a triangle! What a loser! A cone, in general has no line of symmetry. A right cone has one.
A nephroid has 2 lines of symmetry.
it has five lines of symmetry
10 lines of symmetry
4 Lines of symmetry