Designer can use Cartesian (rectangular) or polar (radial) coordinates. In the polar coordinate system, you can express angles in degrees or radians.
Cartesian coordinates use the familiar vertical and horizontal axes. The vertical axis is called Y, and the horizontal axis is called X.
The X and Y axes correspond closely to the rulers in the Designer window. The ruler origin is the intersection of the two axes, where X=0, Y=0. If the origin is set at the top left of a page, the values for X go from left to right, and the values for Y go from top to bottom, just like the rulers.
If you drag the ruler origin to the center of the page, the axes and rulers are repositioned with respect to the page.
Polar coordinates use a different method to reference each point on the page. Instead of having two straight axes, polar coordinates measure the distance from the center and the angle from the axis.
The distance from the center is called R (for radius). R is measured in inches, centimeters, or some other linear unit of measure. Angles are called A and are measured in degrees or radians. Degrees and radians are both radial, rather than linear, units of measure. One radian is equal to approximately 57.3 degrees.
To find a point where R equals 3 and A equals 45 degrees, find 3 at zero degrees and then move along that circle until you reach 45 degrees.
The zero degree point of the polar coordinate system corresponds to Designer's horizontal ruler. The ruler origin is the center of the polar coordinate model. If the origin is set at the top left of a page, the relationship of the system to the page is as shown in the following diagram.
If you drag the ruler origin to the center of the page, the rulers and system are repositioned with respect to the page.
