Department of Mathematics Education
J. Wilson, EMAT 6680

Geometer's Sketchpad (GSP) is a dynamic geometric construction computer software package that has positively influenced not only the study of geometry, but also the study of algebraic topics. GSP's combination of ease of use and extensive features provides users of all ages with a powerful tool in investigating mathematical problems of various complexity. Through construction and manipulation of geometric figures, GSP helps users to visualize, and therefore, discover relationships within a sketch. In addition to being a catalyst for discovery, GSP also is beneficial in creating demonstrations and in developing the concept of a proof.

For more information, contact the publisher, Key Curriculum Press. To see a GSP example, click here and then double-click on "Animate." To find instructions on setting up GSP as a helper application click here.

Regardless of the complexity of the concept, creating and using a GSP script can be important in providing efficiency to an investigation. In addition, scripts can be considered the statements of a two-column proof. Therefore, investigating scripts can also help students to develop the concept of a proof.

The following is a personal library of GSP scripts. I will try to expand the list periodically.

In order to use a script, you must:

1. Double-click on one of the script links. GSP will automatically open with a new sketch, unless you already have GSP opened. If you already have GSP opened, you will be given the option of whether to open another copy of GSP or not.
2. Size your applications, so that you can view both the script and the GSP sketch.
3. Construct the givens listed in the script.
4. Select the givens in the order specified by the script. (Remember to hold the "shift" key down when selecting more than one object.)
5. On the script tool bar, select Fast for the script to be completed quickly, select Play for the script to be completed slow enough to see the steps involved in the script, or repeatedly select Step for the script to construct the figure one step at a time.

• centroid
• orthocenter
• circumcenter
• circumcircle
• incenter
• incircle
• triangle centers (H, G, C, I)
• triangle centers (H, G, C, I) with Euler Segment
• medial triangle
• orthocenter of medial triangle
• orthic triangle
• orthic triangle and the triangle formed by the points where the extended altitudes meet the circumcircle
• pedal triangle
• nine point circle
• center of nine point circle
• trisecting a segment
• n-secting a segment (up to n=7)
• equilateral triangle, given two points
• square, given a side (using only the GSP construction menu)
• square, given a side (using rotations)
• square, given the diagonal
• right triangle, using only the GSP construction menu
• right triangle, using rotations
• isosceles triangle, given base and altitude
• divide a segment into two parts that form a golden ratio
• golden rectangle
• parallelogram, given 3 points
• parallelogram, given a side
• rhombus, given a side
• kite, given a side
• pentagon, given a radius (using only the GSP construction menu)
• pentagon, given a radius (using rotations)
• pentagon, given a side (using rotations)
• hexagon, given a radius (using only the GSP construction menu)
• hexagon, given a radius (using rotations)
• hexagon, given a side (using rotations)
• octagon, given a radius (using only the GSP construction menu)
• octagon, given a radius (using rotations)
• octagon, given a side (using rotations)
• dodecagon, given a diameter (using only the GSP construction menu)
• parabola, given focus and directrix
• ellipse, given focus and directrix
• hyperbola, given focus and directrix
• tangent circle to two circles, internal to larger given circle and external to smaller given circle
• tangent circle to two circles, internal to larger given circle and smaller given circle internal to constructed tangent circle

If you have any suggestions for scripts that would be useful, especially for use at the high school level, please send e-mail to esiwdivad@yahoo.com.

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