The name of a 10 sided polygon is Decagon.
A triangular pyramid.
pentagonal pyramid
I'd recommend "decatrillogon" for ten trillion sides.
A pyramid must have at least four faces (sides) so a three sided pyramid is mathematically impossible.
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
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.
10
The name of a 10 sided polygon is Decagon.
A 10-sided polygon is called a decagon.
A nonagonal pyramid. A pyramid whose base is an n sided poygon will have n+1 faces in all.
if its a four sided pyramid then four. if its a three sided pyramid then four.
Smooth [sided] pyramid Step [sided] pyramid Bent pyramid
A rectangle pyramid is a 4 sided pyramid (4 sided in the triangles) with a base of a rectangle. An Egyptian pyramid is a great example of a rectangular pyramid.