Represents the "A3" entry of the 3d radial dimension measurement object.

It is defined as part of the PDF 1.7 Extension Level 3 specification.

It contains an array which contains doubles, representing PDF numeric objects.

For definitive details see:.

Adobe Supplement to the ISO 32000, BaseVersion: 1.7, ExtensionLevel: 3; Table: 9.39e, page 71.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 330, page 692.

The A3 entry holds a second circumference point used to define the circle geometry when the circular feature is derived from three points.