Calculations in regular tetragonal (4-) and pentagonal (5-) trapezohedrons. The number n of the trapezohedron refers to the number of faces of one half. A trigonal (3-) trapezohedron is the rhombohedron. A trapezohedron (or deltohedron) is a bipyramid, that is twisted in itself for 180°/n. A regular trapezohedron is the dual body of a unifrom antiprism. The faces are 2n deltoids. Choose the type of trapezohedron (4- or 5-), enter one value and choose the number of decimal places. Then click Calculate.

Edge lengths and height have the same unit (e.g. meter), the area has this unit squared (e.g. square meter), the volume has this unit to the power of three (e.g. cubic meter). A/V has this unit ^{-1}.

There is an infinite number of regular trapezohedrons, since the possible number of side faces is unlimited. The more side faces, the rounder the sides become and the flatter the middle division becomes. The regular trapezohedron approaches the bicone as the number of faces increases.
In addition to the regular trapezohedron, there are an infinite number of irregular trapezohedrons, in which the side faces are identical quadrilaterals. All trapezohedrons are point-symmetrical to the intersection of the spatial diagonals of the opposite corners. They have for n>3 no parallel sides and edges and are not axially symmetrical.
The trapezohedron takes its name from the trapezoid. However, this is not meant in its current meaning, where it has two parallel sides. A trapezohedron made of trapezoids according to the modern definition is not possible, since the trapezohedron cannot have parallel edges. In contrast, the original meaning of trapezoid until about the beginning of the 20th century was that of a general quadrilateral and the trapezohedron is named after this meaning.