A triangular pyramid.
pentagonal pyramid
pentagonal pyramid
A pyramid must have at least four faces (sides) so a three sided pyramid is mathematically impossible.
A pyramid is a four-sided 3D triangle
A 7 sided pyramid would be called a heptahedral or heptahedron.
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 four sided pyramid is called a square based pyramid. It has a square base and four sides,(called edges,) that join at the apex. (the top of the pyramid.)
A triangular pyramid.
A pentagonal pyramid.
Hexagon shaped pyramid
A triangular pyramid A triangular pyramid has four sides - each of which is a triangle. There cannot be a three sided pyramid. If you mean a 3 sided Pyramid with its base being the forth side it would be a Quadrangle. A four-sided triangular solid is also called a tetrahedron, and two interlaced are called a Star Tetrahedron.
If you mean a pyramid with a four sided base, it is a square pyramid. If you mean one with four faces, it is a tetrahedron.
A 6 sided planar (2-d) polygon is called a hexagon.A 6 sided 3-d shape is a hexahedron, which might also be a cube, rectangular prism, die, pentagonal pyramid, or quadrilateral di-pyramid depending on the exact shape.
=Pyramid=
a pyramid
pentagonal pyramid