Shape 

Copyright David & Cynthia Thomas, 2009

 

Sides, Angles, Interior Lines & Points--Directed Activity: Perpendicular lines

                                                                

Focus

Construct a line perpendicular to a given line.

Technologies

·        The Geometers Sketchpad

·        Paper and pencil

Background

Perpendicular lines, rays, or segments intersect to form congruent (90°) adjacent angles.   For example, in Figure 2.15, segments IJ and DK are perpendicular to segment AB.  IJ is constructed perpendicular to segment AB at point C on segment AB.  DK is constructed perpendicular to segment AB through point D.

Figure 2.15: Perpendicular Lines

 

Tasks

·        Construct a perpendicular to a given line containing a given point on the line using:

  • Pencil and paper
  • The Geometers Sketchpad. 

·        Construct a perpendicular to a given line containing a given point not on the line using:

o       Pencil and paper

o       The Geometers Sketchpad.