To solve this kind of problem, we must carefully analyze the meaning of the question: 1, draw a line segment, which is 2, 7 cm and 2 mm shorter than 1 decimeter, and 3 calculate: 1 decimeter = 1 centimeter =/kloc-0.

1 decimeter =10cm =100mm.

1 cm = 10/0mm.

7 cm 2 mm =7.2 cm.

10cm-7.2cm = 2.8cm = 2cm 8mm.

In other words, draw a line segment of 2 cm and 8 mm.

relevant knowledge

The general term in technical drawing refers to a continuous or discontinuous drawing line composed of one or more different line elements, such as a solid line segment or a double-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. 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.