Construct a line segment with length 6 cm.
Step 1 : Use a ruler to draw a straight line that is slightly longer than 6 cm. Mark the starting point (P) near the beginning of the line.
Step 2 : Stretch the 2 arms of the compasses on the ruler until the distance between the sharp end and the pencil end is 6 cm apart.
Step 3 : Put the compasses on the line with the sharp end at point P and mark an arc on the line using the pencil end.
Step 4: Remove the compasses and mark the point where the arc meets the line as point Q.
Note : While it may be easier to construct the line segment by simply marking off 6 cm with a ruler, this technique of using compasses is essential for other construction lessons.
The following video shows how to construct a line segment of a given length, on a given ray.
The following video shows how to copy a line segment using only a compass and straightedge.