In geometry, a shape is a graphical representation of an object or its external boundary, outline, or external surface, as opposed to other properties such as color, texture, or material type. A figure is a representation including both shape and size. Shapes can be classified into basic geometric objects such as a point, a line, a curve, a plane, a plane figure (e.g. square or circle), or a solid figure (e.g. cube or sphere) .
Three-dimensional (3D) shapes are solid shapes that have three dimensions including length, depth, and width. They are shapes that occupy space and have volume. 3D shapes have faces, edges, and vertices. They have a surface area that includes the area of all their faces. Some examples of 3D shapes are a cube, cuboid, cone, cylinder, sphere, pyramid, prism, and so on.
In contrast, two-dimensional (2D) shapes are flat shapes that have only two dimensions, such as length and width. Examples of 2D shapes include triangles, squares, and pentagons.
