Short answer: there isn't one. The polyhedron with the smallest number of faces (which is probably what you mean) is the tetrahedron, which has four faces.
Maybe you meant polygon, in which case the answer is a triangle.
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.
Because that is how a polyhedron is defined.
There is no polyhedron with only three sides - a polyhedron being a 3-D shape with plane sides. Once you remove the restriction of plane sides you get several options, some of which are: A cylinder or a cylindrical shape with partial spheres at each end (like a medicine capsule). A segment of a torus (a doughnut with a chunk cut out of it). A spherical wedge - like a segment of a round cheese (that is, real cheese, not the processed plastic that some people consider cheese).
a 3d objet with all flat sides
A Pyramid; Four sides and the base.
No. A polyhedron is 3 dimensional. You have a regular polygon, regular because the sides are equal. If you asked about 20 surfaces, then it would be a polyhedron.
Heptahedron.
A polyhedron is a solid shape with many sides. The word "polyhedron" does not specify a number of sides.
A polyhedron has "many sides" (by definiton). The only 3-D shape which does not have "many sides" is a sphere (which technically only have one "side").
They are the faces of the polyhedron.
It is a polyhedron with two congruent sides: nothing more, nothing less.
The sides of a rectangle are not all equal so a rectangle is not a regular polygon. And, as a consequence, any 3-dimensional shape made from rectangles cannot be a regular polyhedron.
It is not a regular polyhedron because it has unequal sides
A polyhedron with 5 faces could be called a pentahedron, but a more common name would be a quadrilateral pyramid. A square pyramid is a special case of such a shape.
How many sides does it have altogether? If it just has the 2 angles and side and 3 corners, there is no polyhedron with that discription.
No polyhedron has five sides as a pentagon and a hexagon has six sides
I believe the correct term would be a "polyhedron".