What is 2D?
2D is short for two-dimensional. A two-dimensional space is a mathematical space with two dimensions – length and width. Common two-dimensional spaces are often called planes, or, more generally, surfaces.
These are common 2D shapes. Most of the shapes have sides, points, and angles at the connecting sides. Circles have a circumference and a radius.
2D shapes can be drawn in coordinate systems. A two-dimensional coordinate system includes a plane made up of a grid with an x- and a y-axis.
This vdieo explains a 2D coordinate system. The narrator defines the axes, ordered pairs, the origin, and quadrants.
What is 3D?
3D is short for three-dimensional. A three-dimensional space is a mathematical space in which three values (coordinates) are required to determine the position of a point. Most commonly, it is the three-dimensional Euclidean space, which models physical space. The term may also refer to a solid figure.
Three dimensional space is a useful way to model the world as it is experienced. In this classical example, when the three values refer to measurements in different directions (coordinates), any three directions can be chosen, provided that these directions do not lie in the same plane. Furthermore, if these directions are pairwise perpendicular, the three values are often labeled by the terms width/breadth, height/depth, and length.
These are common 3D shapes. Most of these shapes also have sides, points, and angles at the connecting sides but they are shapes that have greater surface areas, along with volume and mass.
3D shapes can also be drawn in coordinate systems. A three-dimensional coordinate system includes a plane made up of a grid with an x-, y-, and z-axis.
This is a good video that explains how to plot points in a 3D coordinate system. The narrator also explains how to use the distance formula with z-axis points.