1. Select the endpoints to count sequentially (from left to right or from right to left).

(1) Starting from point A, the number is 4.

(2) Starting from point B, the numbers are 3 in turn.

(3) Starting from point C, the numbers are 2 in turn.

(4) Starting from point D, the number is 1.

4+3+2+ 1= 10 (articles), the answer is 10.

2. Count the basic line segments first, and then the combined line segments.

(1) has four basic line segments: AB, BC, CD and DE.

(2) There are two basic line segments: AC, BD and CE.

(3) There are three basic line segments: AD and BE.

(4) There are four basic line segments: AE has 1.

4+3+2+ 1= 10 (articles), the answer is 10.

Line segment, a general term in technical drawing, refers to a continuous or discontinuous drawing line composed of one or more different line elements, such as a real line segment or a two-point long line segment composed of "long stroke, short interval, point, short interval, point and short interval". Connect two points with a ruler and you get a line segment.

The length of a line segment is the distance between these two points. The length of the line segment connecting two points is called the distance between these two points. Line segments are represented by letters A and B or lowercase letters representing their two endpoints. Sometimes these letters also represent the length of the line segment, which is recorded as line segment AB or line segment BA, line segment A .. where A and B represent the two endpoints of the line segment.