Fig. 43.
Fig. 44.
Figs. 45-49.
A Rhomboid is an oblique-angled parallelogram.
A Rhombus is an equilateral rhomboid, [fig. 42].
A Trapezium is a quadrilateral having no two sides parallel, [fig. 43].
A Trapezoid is a quadrilateral in which two opposite sides are parallel, and the other two oblique, [fig. 44].
A POLYHEDRON is a solid bounded by planes. There are five regular solids which are shown in [figs. 45, 46, 47, 48 and 49]. A regular solid is bounded by similar and regular plane figures.