A square-based pyramid
pyramid
A pyramid - it has a square base, and four triangles meeting to a point at the top.
triangular prism
triangular prism
tetrahedron
pyramid
pyramid
A pyramid - it has a square base, and four triangles meeting to a point at the top.
A triangular prism, where the two ends are triangles.
triangular prism
triangular prism
tetrahedron
An octahedron can have faces which are triangles, quadrilaterals, pentagons, hexagons or heptagons,
An Icosahedron.
An octahedron
Triangular prism
Well, any shape with a triangular face. I assume that you mean a shape that only has (identical) triangles for faces. There are 2: the tetrahedron with 4 triangles, and the icosahedron with 20 triangles. * * * * * What about a triangular dipyramid? Two triangular pyramids stuck together along one face?