What is a z-coordinate?

Hint: From the question we have been asked what is a z-coordinate. For solving this question we will explain the coordinate system in the \[3-D\] or simply three dimensional coordinate system. We will take the help of the \[3-D\] or three dimensional coordinate system figure and we explain the z-coordinate and its properties and thus we solve the given question. So, we proceed with the solution as follows.

Complete step-by-step answer:
We are probably familiar with the \[x-y\] Cartesian coordinate system. This is a two dimensional coordinate system which usually has a flat plane and any point on this plane can be plotted or identified using two coordinates which are \[x-y\] coordinates.
Whereas the \[z\] coordinates are found in a special geometric setting called the three dimensional plane or space.
For this three dimensional plane there are three coordinates which are namely \[x,y,z\] coordinates.
Unlike in the two dimensional flat \[x-y\] plane, to identify or plot any point or a location in the three dimensional space we need three parameters which are \[x,y,z\] coordinates.
The figure of the three dimensional plane will be as follows.

The points in this plane would be of the form \[\left( x,y,z \right)\].

Note: Students should have good knowledge in the concept of coordinate plane mainly about the three dimensional coordinate plane. We must be able to correlate the two dimensional or Cartesian coordinate plane to the three dimensional plane which helps us in understanding and solving the problem easily.