Shape 

Copyright David & Cynthia Thomas, 2009

 

Triangle Recipes--Directed Activity: Duplicate a Segment of Unknown Length

                                      

Focus

Duplicate a segment of unknown length in a different location.

Technologies

·        Straightedge-and-compass

·        The Geometers Sketchpad

References

·        Euclid’s Elements

http://aleph0.clarku.edu/~djoyce/java/elements/toc.html

·        Euclid of Alexandria

http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Euclid.html

Background

In Figure 1.10, the distance between points A and B may not be measured directly because of an intervening pile of dirt. 

Figure 1.10: Duplicating a Segment of Unknown Length

 

Tasks

1.      Devise a method for determining the length of segment AB by constructing and measuring a duplicate segment A’B’ in a different location. 

2.      Explain and justify your construction and the final result.