Write Up 5

A Library of GSP Scripts

by: Angel R. Abney

Using GSP scripts is a more efficient way of repeating constructions rather than completing the construction from scratch several times. Below is a library of GSP scripts that can be used as tools for doing several different constructions. Note, to use the scripts you must have Geometer's Sketch Pad on your compter. Each script will have a set of given geometric objects. Open a sketch, by clicking on the blue underlined term, and select the objects in the order specified in the givens. Then select Play on the script.

1. Centroid - the centroid, G, is the intersection of the medians of a triangle.

2. Orthocenter - the orthocenter, H, is the intersection of the altitudes of a triangle.

3. Circumcenter - the circumcenter, C, is the intersection of the perpendicular bisectors of a triangle.

4. Circumcircle - circle with center , circumcenter, C, and vertices of the triangle are points on the circle.

5. Incenter - the incenter, I, is the intersection of the angle bisectors of a triangle.

6. Incircle - circle with center, incenter, I, and feet of perpendicular lines from the incenter to the sides of the triangle are points on the circle.

7. Medial Triangle - the medial triangle is constructed by connecting the mid-points of each side of the triangle.

8. Orthocenter, Mid-segment triangle- the mid-segment triangle is constructed by connecting the mid-points of the segments from the orthocenter to the vertices.

9. Orthic Triangle - The orthic triangle is constructed by connecting the feet of the altitudes of a triangle.

10. Pedal Triangle - Given a triangle ABC and any point E in the plane, the triangle formed by the perpendiculars to the sides of ABC is called the
Pedal triangle for the pedal point E.

11. Center of Nine Point Circle -the mid-point of the Euler Line formed from the centers of a triangle.

12. Nine Point Circle - circle formed from the centers of a triangle.

13. Trisecting a Line Segment

14. Equilateral Triangle, given a side

15. Square, given a side

16. Isosceles triangle, given base and altitude

17. Triangle Centers (H,G,C, and I)

18. Triangle Centers with Euler Line - The Centers of a triangle, H(orthocenter), G(centroid), and C(circumcenter) always lie in a line called the Euler Line.