3-D Coordinate System
In the 3-D Coordinate System, also denoted as , we have 3 axis . We draw the axis' in the graph like this: 
 
 
Points are written in the form  
Planes
The -plane corresponds to all the points at which .
The -plane corresponds to all the points at which .
The -plane corresponds to all the points at which . 
These planes are sometimes called "coordinate planes". 
Projection of a Point
When a point  gets projected onto a plane, then the point will be on the plane. 
For example, the projection of point  onto the -plane will become . 
Distance of Two Points
To find the distance between two points in , we use the formula:
Where the two points are and .
Other General Equations in 3D
Here are the general types of equations you might see in the 3-D Coordinate system:
- Cylinder: 
   
 Points are written in the form
- Sphere: 
   
 Points are written in the form
- Plane: 
   






