Notes for Visualising Solid Shapes

F + V � E = 2

where �F� stands for number of faces,

�V� stands for number of vertices and

�E� stands for number of edges.

Plane shapes have two dimensions (measurements) like length and breadth. That is why they are called two dimensional (2-D) shapes. On the other hand, a solid object having three dimensions like length, breadth, height (or depth) is called 3-D object. Triangles, rectangles, circles, trapeziums, etc. are 2-D Figures while cuboids, cubes, cylinders, spheres, etc. are 3-D objects. A solid is bounded by one or more surface and it always occupies some space. Its surface (or face) can be a plane or a curved surface. When any two faces of a solid meet together, we get a line segment called an edge. When three more faces of a solid meet at one point, then the point is called a vertex of the solid.