How do you name shapes? - Answers

There are a wide range of shapes, in 2 and 3 dimensions. 2 dimensional shapes with sides that are straight lines are called polygons. In most cases the first part of their name is the Greek word for the number of sides followed by the suffix -gon. Triangles and quadrilaterals have additional special names depending on their characteristics - for example, right angled isosceles triangle or parallelogram. Polygons with more 5 or more sides are generally classified into regular (all sides equal AND all angles equal) or irregular (some sides unequal or some angles unequal or both). Then there are shapes not bounded by straight lines such as a circle, ellipse, oval, and many other less well known shapes and finally the totally random, wriggly shape! In 3 dimensions, the nomenclature gets more complicated. Shapes bounded by plane faces are called polyhedra and they are named after the Greek name for the number of faces followed by the suffix -hedron. As in the case of polygons with a small number of sides, there are special names for some of the polyhedra with fewer sides. Pyramids and prisms are two classes of polyhedra. They can be triangle based, quadrilateral based, pentagon based and so on. There are also 3-d versions of other shapes: the sphere, cone, ellipsoid, cylinder, torus (doughnut shape) are some examples. And finally, there is the 3-d counterpart of the wriggly shape which goes under the technical name of the blob!