Prismatoid

A Polyhedron having two Polygons in Parallel planes as bases and Triangular or Trapezoidal lateral faces with one side lying in one base and the opposite Vertex or side lying in the other base. Examples include the Cube, Pyramidal Frustum, Rectangular Parallelepiped, Prism, and Pyramid. Let $A_1$ be the Area of the lower base, $A_2$ the Area of the upper base, $M$ the Area of the midsection, and $h$ the Altitude. Then

$$V={\textstyle{1\over 6}} h(A_1+4M+A_2).$$

See also General Prismatoid, Prismoid

References

Beyer, W. H. CRC Standard Mathematical Tables, 28th ed. Boca Raton, FL: CRC Press, pp. 128 and 132, 1987.