

Copying a line segment
Geometry construction using a compass and straightedge
This page shows how to copy a line segment with compass and straightedge or ruler. Given a line segment, this shows how to make another segment of the same length.
Printable stepbystep instructions
The above animation is available as a
printable stepbystep instruction sheet, which can be used for making handouts
or when a computer is not available.
Proof
The proof of this construction is trivial. Refer to the figure above in step 8.

Argument 
Reason 
1 
All points along the the arc S are the same distance from R 
R is the center of the arc. See Arc definition 
2 
This distance is equal to the length of segment PQ 
The arc was drawn with that compass width 
3 
RS is congruent to PQ 
S is a point on the arc. See (1). 
 Q.E.D
Try it yourself
Click here for a printable worksheet containing two line segment copying problems.
When you get to the page, use the browser print command to print as many as you wish. The printed output is not copyright.
Other constructions pages on this site
Lines
Angles
Triangles
Right triangles
Triangle Centers
Circles, Arcs and Ellipses
Polygons
NonEuclidean constructions
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