To understand what constitutes a golden section, consider the top line segment shown on the next page. The line segment has three of its points marked. Point P partitions the line segment AB into two smaller segments: from left endpoint A to point P (AP), and from P to right endpoint B (PB). The line segments AP and PB are also shown individually.

A "golden ratio" can now be formed as the ratio of one line segment to another line segment. Point P divides the entire line segment AB into a golden section if the following equation is valid:

AP/AB = PB/AP.

In other words, the length of line segment AP divided by the length of the entire line segment AB is a ratio, or number, and that number is the same as the ratio of the shortest line segment PB and the segment AP...