You cannot use a regular octagon on it's own to make a tiling pattern without any gaps. However a regular Octagon and a square can be used together to make a tessellation. Many people think that regular octagons tesselate on their own because they do not appreciate the need for no gaps.
No, they will not fit together, you will also need a square with sides equal in length to the sides of the octagon.
True * * * * * No. The only regular polygons that will tessellate are a triangle, a square and a heagon. So a regular heptagon will not tessellate.
No it does not tessellate you have to pentagons in order for it to tessellate. * * * * * It is not at all clear what "have to pentagons" has to do with this. No polygon with 7 or more sides will tessellate. Octagons will tessellate if mixed with squares but that is not "proper" tessellation since it involved more than one shape.
YES
To turn a 9x9 square into an octagon you can cut corners off the square. It will not be a regular octagon though.
Square.
square and octagon
No, but an octagon and a square can tessellate.
A regular octagon will not tessellate but an irregular one can.
An octagon can be used to create a tessellation, but an octagon cannot tessellate on its own.
No, it can't be tessellate.
Yes, it will.
A regular octagon will not tessellate but an irregular one can.
A regular octagon will not tessellate but an irregular one will.
A regular octagon will not tessellate but an irregular one can.
no
No