its called a base.
a pyramid is 3d
A hexagonal pyramid
a pyramid
The difference is the shape. A cube is a 3D square. A square pyramid is a pyramid with for sides and a square on the bottom.
Pyramid
A hexahedron has a triangular pyramid on top and on bottom and share the bases.
Triangular Pyramid.
Triangular pyramid
A triangular pyramid. It has triangles on its 3 sides and a triangle on the bottom for a base.
a pyramid is a 3D shape :)
That 3D shape is called triangular pyramid.
It's a Pentagonal Prism or Pyramid.