Solids are shapes that you can actually touch. They have three dimensions, which means that the have length, width and height. These shapes are what make up our daily life, and are very useful. Points on a solid must not be coplanar or colinear. The edge of solids are called the edge, and the surfaces are called faces. The corners, like angles and plane figures, are called vertices.
A solid with only straight edges is called a polyhedron(pol-ee-HEE-dron). The plural form of polehedron is polyhedra(pol-ee-HEE-drah). Your chocolate bars are polyhedra, The Great Pyramids are polyhedra – a lot of things are. We will go into detail about them later.
When dealing with these solid figures, there are two measurements we will need to know: the total surface area and the volume. The former is the sum of the faces of the solid; the latter is how big the solid is.

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