There are five regular polyhedra, also known as the Platonic solids. They are three-dimensional shapes where all of the faces are made up of the same regular polygon.
They are:
A square pyramid (like the Egyptian pyramids) is not a regular polyhedron, because it has two different types of regular polygons for faces.
Yes and its names is a tetrahedron.
Yes.
A triangle is not a polyhedron. A triangle is a two-dimensional figure, and a polyhedron is a three-dimensional solid. An example of a triangular-shaped polyhedron is a pyramid.
It is a polyhedron.
No, a sphere is not a polyhedron.A polyhedron is a three-dimensional geometric figure whose sides are polygons.A regular polyhedron is a polyhedron whose faces are all congruent regular polygons.
Yes. A polyhedron is a geometric shape with flat surfaces and straight edges, so a a pyramid with a rectangular base qualifies as a polyhedron. It is however not a regular polyhedron, which would require all the faces to be the same shape and size. To change your pyramid to a regular polyhedron you'd have to turn it into a tetrahedron.
Yes and its names is a tetrahedron.
A regular polyhedron has equal size faces as in the case of a tetrahedron which is a triangular base pyramid that has 4 equilateral triangle faces.
There are regular and irregular pyramids. The famous ones at Gizeh are regular, but just because it's a pyramid, it doesn't necessarily have to be regular.
A solid figure with many sides such as a pyramid
A polyhedron is a simply connected 3-dimensional shape whose faces are all regular polygons. A hexagonal pyramid is a special case in which one face is a hexagon and six faces are triangles.
A regular polygon has equal sides and angles. A polygon has a surface area but a polyhedron has many faces as for example a pyramid.
Yes.
No, but a pyramid is.
A pyramid, as well as any other solid figure bounded by plane polygons or faces, is a polyhedron.
A regular polyhedron (other than a hexahedron), any pyramid, as well as most irregular polyhedra.
No. A pyramid is a polyhedron. Many pyramids are polyhedra.