Enter 2D Coordinates
Enter absolute coordinate
Absolute coordinates are based on the UCS origin (0,0), which is the intersection of the X and Y axis. If you know the precise X and Y values of the point, you can use absolute coordinates.
Enter relative coordinate
The last point entered is used as a base for Relative coordinates and you can use them, if you know the location of a point in relation to the previous point.
Enter Polar Coordinates
When creating objects, you can use absolute or relative polar coordinates (distance and angle) . The distance and the angle separated by an angle bracket (<) when you use polar coordinates to specify a point.
Absolute polar coordinates are based on the origin.
Relative coordinates are based on the last point entered. If you know the location of a point in relation to the previous point, you can use relative coordinates.