Pyramid
The figure is a pyramid and the base is a square.
The answer is a pyramid.
Pyramid. Work: 4 sides (that you usually see) are triangles, the base (bottom) is a square
octagonal pyramid
There is a contradiction in your question. If the base has four equal sides then is it a square so not all the faces are Triangles. However if the base is a square and the rest of the faces are triangles then your object is a "Square-based Pyramid"
A pyramid with a triangular base. The faces are 4 equilateral triangles.
A regular pentagon-based pyramid.
a pentagonal pyramid it has five triangular sides that all meet at a point at the top. the base is a pentagon
Not necessarily. The solid could be a square based cuboid (hexahedron).
A pyramid.
A triangular pyramid. It has triangles on its 3 sides and a triangle on the bottom for a base.
A pyramid.