A square pyramid.
The 7-letter word for a 3D shape with triangular faces is "pyramid." A pyramid is a polyhedron with a polygonal base and triangular faces that meet at a common vertex called the apex. Pyramids are classified based on the shape of their base, such as square pyramids, triangular pyramids, pentagonal pyramids, etc.
The 3D shape you are describing is a pentagonal pyramid. It has a pentagonal base with five sides, and five vertices where the triangular faces meet. The three rectangle faces are lateral faces that connect the triangular base to the apex of the pyramid. The pentagonal pyramid is a type of pyramid with a polygonal base and triangular faces.
A triangular prism, a triangle base and three triangular faces (a tetrahedron)The figures below do not strictly have a "base" but they are composed entirely of trianglesAn octohedron (eight sides)An isocahedron (20 identical equilateral triangular faces, 30 edges and 12 vertices)Any of a number of deformations of the above
It is a triangular prism
A triangular prism can have a square or triangular base.
the base of a triangular pyramid is triangle
the base of a triangular pyramid is triangle
If it is a pyramid, then the base shape is a SQURE. If it is a tetrahedron, then the base shape is a triangle.
Triangular Pyrimid
A triangular prism can have a square or triangular base, but faces are normally triangles. (I think)
That would be a triangular pyramid.
It is a pyramid
It is normally rectangular in shape.
Triangular Pyramid
It is rectangular
Tetrahedron