A nonagon based pyramid.
Nonagon
A triangular pyramid.
pentagonal pyramid
A pyramid must have at least four faces (sides) so a three sided pyramid is mathematically impossible.
An octagonal pyramid would have 9 sides: an octagon as the base and 8 triangles from that base to the apex of the pyramid.
A 7 sided pyramid would be called a heptahedral or heptahedron.
A nonagon based pyramid.
Hexagon shaped pyramid
well actually it is a prism. If you mean a 5 sided pyramid with the 6 side being the bottom it would be called a Pentagonal Pyramid
A pyramid
a 9 sided shape is a nonagon
10
if its a four sided pyramid then four. if its a three sided pyramid then four.
Nonagon.
A nonagon.
Smooth [sided] pyramid Step [sided] pyramid Bent pyramid