Z-Axis - GCSE Maths Definition

To represent three-dimensional space and/or shapes graphically, a third-dimension (after x and y) would be required. On a 3D graph, the third axis is usually the z-axis. The origin will be where z = 0, x = 0 and y = 0. The values on the z-axis can be positive or negative, depending on its use. The z-axis does not have a particular direction (nor do x and y in 3D) as when drawing 3D graphs we are likely to be using powerful graphic calculators or computer software that allow us to rotate the axes in any way we choose. This is important in designing any 3D object (i.e. almost everything) where different views can reveal different features of the object.

In GCSE Mathematics, identifying a third (z-) axis and values on it, can help visualise how vertices, faces and edges on a 3D shape (such as a cuboid or triangular prism) relate to each other; this enables us to solve questions involving side lengths, surface areas and volume.