Do Edges Have to Be Straight?

An edge is where 2 faces meet, again some can be straight, some can be curved e.g. a cube has 12 straight edges whereas a cylinder has 2 curved edges. A sphere has no edges and therefore no corners. It has one curved face that goes all the way around.

Can an edge be curved?

An edge is the place where two faces meet. Edges are straight; they cannot be curved.

In geometry, the term ‘face’ refers to a flat surface with only straight edges, as in prisms and pyramids, eg. a cube has six faces. Curved surfaces, such as those found in cylinders, cones, and spheres, are not classified as ‘faces’.

Do vertices have to be straight?

A two-dimensional shape, such as a triangle, is composed of two parts – edges and vertices. The edges are the lines that make up the boundary of the shape. Each point where two straight edges intersect is a vertex. You can also see from this definition that some two-dimensional shapes do not have any vertices.

Although a cylinder has two faces, the faces don’t meet, so there are no edges or vertices.