i’m doing geometry this year, and we’ve pretty much gotten out of all the polyhedron crap for now. but i was wondering about 2 shapes my geometry teacher cannot identify.

if you take a right circular cone, and stretch the base to an oval rather than a circle, and then stretch the vertex into a line segment rather than a point, what shape do you get?

have you ever seen one of those weird popsicles in a paper pouch? okay, this one is a little harder to describe. if you take a cube and flatten the top face into a line segment from left to right, you’ll get a triangular prism. but when you flatten the base of the prism into a line prependicular to the line segment opposite the base, what do you get, specifically? i think this one is some kind of tetrahedron with 4 tirangular faces, but is there a specific name for it?

#2 is a tetrahedron with four isosceles triangles for faces. These will necessarily be congruent. It does qualify as an Isosceles Tetrahedron. However, not all Isosceles Tetrahedra are of this form.

I’m sorry, I realize now this is not true. The OP describes a tetrahedron with four congruent isosceles triangles for faces. But I was wrong; not all tetrahedra with four isosceles faces will have all faces congruent.

The OP’s shape is what you’d get if you took a regular tetrahedron, held two vertices between your thumb and forefinger of one hand, held the other two vertices between your thumb and forefinger of your other hand, and pulled.

[slight_hijack]wolf_meister, have you heard of a new term being used? It is “conamyds” and is used to describe what I think is properly termed a truncated cone; in other words, a cone with the tip cut off. Nice website, BTW.[/slight_hijack]