six, you need six
24
You'll need 18 straws because it has 18 edges
The apex, and the shape of the base does not make a difference to what it is called.
An equilateral triangle based anti prism is simply a "normal" octahedron, as described by someone trying to make things sound more complicated than they are. It has 6 vertices.
8
18 straws.
15
24
9
15 straws are needed
You'll need 18 straws because it has 18 edges
The apex, and the shape of the base does not make a difference to what it is called.
6
10
An equilateral triangle based anti prism is simply a "normal" octahedron, as described by someone trying to make things sound more complicated than they are. It has 6 vertices.
8 straws.
You need nine sides, so nine straws. But you could just use one straw and cut it into nine pieces.