Pyramid
Triangle
A tetrahedron = triangle based pyramid.
By its very nature of being a triangle, and a 2D shape, a triangle cannot have four plane faces. However, a tetrahedron is a polyhedron made up of four triangular faces.
A tetrahedron is the smallest possible polyhedron: a closed 3-d shape with polygonal faces. It has 4 triangular faces, 4 vertices and 6 edges. It is also known as a triangle-based pyramid.
Regular Tetrahedron
four triangle faces.
No, a triangle does not have three faces; it is a two-dimensional shape with three sides and three angles. In three-dimensional geometry, the term "face" refers to the flat surfaces of a solid object, such as a tetrahedron, which has four triangular faces. A triangle itself exists only in a plane and does not have any volume or faces like a three-dimensional shape.
tetrahedron
A tetrahedron has four faces. Each face is a triangle, and the tetrahedron is a type of polyhedron that is the simplest three-dimensional shape. It also has four vertices and six edges.
A pyramid has a variable number of triangular faces. The base of a triangle can be practically any regular shape, starting with a triangle. Technically a pyramid can have four or more triangles as faces.
The answer is a polyhedron
a pyramid