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  2. Cayley–Menger determinant - Wikipedia

    en.wikipedia.org/wiki/Cayley–Menger_determinant

    In linear algebra, geometry, and trigonometry, the Cayley–Menger determinant is a formula for the content, i.e. the higher-dimensional volume, of a -dimensional simplex in terms of the squares of all of the distances between pairs of its vertices. The determinant is named after Arthur Cayley and Karl Menger.

  3. Tetrahedron - Wikipedia

    en.wikipedia.org/wiki/Tetrahedron

    The volume of a tetrahedron can be obtained in many ways. It can be given by using the formula of the pyramid's volume: =. where is the base' area and is the height from the base to the apex. This applies for each of the four choices of the base, so the distances from the apices to the opposite faces are inversely proportional to the areas of ...

  4. Trirectangular tetrahedron - Wikipedia

    en.wikipedia.org/wiki/Trirectangular_tetrahedron

    If the legs have lengths a, b, c, then the trirectangular tetrahedron has the volume [2] =. The altitude h satisfies [3] = + +. The area of the base is given by [4] =. The solid angle at the right-angled vertex, from which the opposite face (the base) subtends an octant, has measure π /2 steradians, one eighth of the surface area of a unit sphere.

  5. Ideal polyhedron - Wikipedia

    en.wikipedia.org/wiki/Ideal_polyhedron

    The volume of an ideal tetrahedron can be expressed in terms of the Clausen function or Lobachevsky function of its dihedral angles, and the volume of an arbitrary ideal polyhedron can then be found by partitioning it into tetrahedra and summing the volumes of the tetrahedra. [11]

  6. Truncated tetrahedron - Wikipedia

    en.wikipedia.org/wiki/Truncated_tetrahedron

    Given the edge length .The surface area of a truncated tetrahedron is the sum of 4 regular hexagons and 4 equilateral triangles' area, and its volume is: [2] =, =.. The dihedral angle of a truncated tetrahedron between triangle-to-hexagon is approximately 109.47°, and that between adjacent hexagonal faces is approximately 70.53°.

  7. Reeve tetrahedra - Wikipedia

    en.wikipedia.org/wiki/Reeve_tetrahedra

    All vertices of a Reeve tetrahedron are lattice points (points whose coordinates are all integers). No other lattice points lie on the surface or in the interior of the tetrahedron. The volume of the Reeve tetrahedron with vertex (1, 1, r) is r/6. In 1957 Reeve used this tetrahedron to show that there exist tetrahedra with four lattice points ...

  8. List of formulas in elementary geometry - Wikipedia

    en.wikipedia.org/wiki/List_of_formulas_in...

    This is a list of volume formulas of basic shapes: [4]: ... Tetrahedron – , where is the side's length. Sphere. The basic quantities describing a sphere ...

  9. Orthocentric tetrahedron - Wikipedia

    en.wikipedia.org/wiki/Orthocentric_tetrahedron

    The four altitudes of an orthogonal tetrahedron meet at its orthocenter. Edges AB, BC, CA are perpendicular to, respectively, edges CD, AD, BD. In geometry, an orthocentric tetrahedron is a tetrahedron where all three pairs of opposite edges are perpendicular. It is also known as an orthogonal tetrahedron since orthogonal means