Aperiodic set of prototiles seen on the list of aperiodic sets of tiles. The underlying undecidability of the domino problem implies that there exists no systematic procedure for deciding whether a given set of tiles can tile the plane. Polygons are plane figures which are bounded by straight line segments. Regular polygons have all sides of equal length as well as all angles of equal measure. As early as AD 325, Pappus of Alexandria knew that only 3 types of regular polygons (the square, equilateral triangle, and hexagon) can fit perfectly together in repeating tessellations on a Euclidean plane. Within that plane, every triangle,
Frustum volume of a pyramidal frustum whose bases are "n"-sided regular polygons is where "a" and "a" are the sides of the two bases. For a right circular conical frustum and where "r" and "r" are the base and top radii respectively, and "s" is the slant height of the frustum. The surface area of a right frustum whose bases are similar regular "n"-sided polygons is where "a" and "a" are the sides of the two bases. Frustum In geometry, a frustum (plural: "frusta" or "frustums") is the portion of a solid (normally a cone or pyramid) that lies between one