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.
A triangular based based pyramid is a TETRAHEDRON. It becomes a regular tetrahedron if the four triangles, that make up its shape, are REGULAR, that is they are all the same size by area and shape; that is they are congruent. The word 'polyhedron' means a solid shape of any number of sides.
Yes.
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.
Square Based PyramidTetrahedron: A tetrahedron is a polyhedron made of 4 triangles. A "regular tetrahedron" is a tetrahedron where the triangles are equilateral. (A polyhedron is any 3 dimentional figure made of flat surfaces and straight lines.)
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.
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 triangular based based pyramid is a TETRAHEDRON. It becomes a regular tetrahedron if the four triangles, that make up its shape, are REGULAR, that is they are all the same size by area and shape; that is they are congruent. The word 'polyhedron' means a solid shape of any number of sides.
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.