MTED 2800/3900
Fall 2004

Sketchpad Assignment 2


These summaries recap two introductory lessons with advanced seventh-graders in which Geometer's Sketchpad was used as a tool.

Part I

  1. Go through the materials using Sketchpad to re-enact each situation.  Play with the constructions and reflect on the instructional interactions described in the summaries.
  2. Re-read the discussions. If you only read the discussions without having played with the situation then you will not have a clear sense of these students' experiences, and hence you will not have a clear sense of how the discussions were grounded in the studentsÕ experiences.
  3. What "big ideas" did these students encounter? (Some of these ideas might not have been discussed explicitly, but are there nevertheless.)

Part II Practicing basic constructions.
  1. Practice these constructions using Sketchpad. Click on the links to download GSP sketches that get you started. :
    1. Given a segment, a line, and a point on the line, duplicate the segment so that the duplicate is on the given line with the given point as one endpoint.
    2. Given an angle, a line, and a point on the line, duplicate the angle so that the angle has one side on the given line the given point as its vertex.
    3. Duplicate a triangle given three sides
    4. Duplicate a triangle given two sides and the angle they form.
    5. Duplicate a triangle given one side and two angles that contain that side.

  2. Play with the AAS Ambiguity sketch to understand why "Angle-Angle-Side" is an ambiguous relationship and is sufficient to guarantee similarity of two triangles, but not congruence.