Understanding Elementary Shapes - Three Dimensional Shapes (Faces, Edges, Vertices)

Three-dimensional (3D) shapes are solid objects that occupy space and have three dimensions: length, width (or breadth), and height. Unlike flat 2D shapes, these objects have volume and can be seen from different angles.

A face is a flat surface of a solid shape. For example, a cube is bounded by $6$ identical square flat surfaces. Some shapes, like spheres or cylinders, also have curved surfaces.

An edge is a line segment where two faces of a solid meet. Visually, these are the 'lines' that define the skeleton of the shape. A cuboid has $12$ such edges where its rectangular faces join.

A vertex (plural: vertices) is a point where three or more edges meet, forming a corner. In a cube or cuboid, there are $8$ such sharp corners where the edges intersect.

A Cube is a special solid where all $6$ faces are equal squares. It has $12$ edges of equal length and $8$ vertices. A Cuboid is similar but its faces are rectangles, and it also possesses $6$ faces, $12$ edges, and $8$ vertices.

A Prism is a polyhedron with two congruent and parallel faces called bases. A Triangular Prism has $2$ triangular bases and $3$ rectangular lateral faces, resulting in $5$ faces, $9$ edges, and $6$ vertices.

A Pyramid has one base (a polygon) and other faces are triangles meeting at a single point called the apex. A Square Pyramid has $1$ square base and $4$ triangular faces, totaling $5$ faces, $8$ edges, and $5$ vertices.

A Triangular Pyramid (also called a Tetrahedron) has a triangle as its base and $3$ triangular faces meeting at the top. It is the simplest polyhedron with $4$ faces, $6$ edges, and $4$ vertices.