Exploration 5: Geometer's Sketchpad Scripts
by Elizabeth Gieseking
This page contains links to several different Geometer's Sketchpad files which contain useful tools for constructions.
Triangle Centers - This file contains 10 different tools
Incenter ERG- This tool marks the incenter of a triangle
Incircle ERG- This tool marks the incenter and constructs the incircle.
Circumcenter ERG - This tool marks the circumcenter of a triangle
Circumcircle ERG - This tool marks the circumcenter of a triangle and constructs the circumcircle
Centroid ERG - This tool marks the centroid of a triangle
Centroid with contruction ERG - This tool marks the centroid of a triangle and its medians
Orthocenter ERG - This tool marks the orthocenter of a triangle
Orthocenter with construction ERG- This tool marks the orthocenter of a triangle and the lines containing the altitudes
Four centers ERG - This tool marks the incenter (I), circumcenter (C), centroid (G), and orthocenter (H)
Special Triangles - This file contains the following special triangle tools
Medial Triangle ERG
Pedal Triangle ERG
Orthic Triangle ERG
Isoceles Triangle - Creates an isosceles triangle, given the base and altitude.
Regular Polygons - This file contains the tools to contruct the following regular polygons, given one of the sides
Equilateral Triangle ERG
Square ERG
Regular Pentagon ERG
Regular Hexagon ERG
Regular Octagon ERG
Inscribed Polygons - This file contains the tools to construct an inscribed regular polygon, given the circle center and a point on the radius
Inscribed Equilateral Triangle ERG
Inscribed Square ERG
Inscribed Regular Pentagon ERG
Inscribed Regular Hexagon ERG
Inscribed Regular Octagon ERG
Ratio Tools
Golden Ratio - This file contains two tools
Golden ratio divider ERG- this divides a given segment into two parts such that the longer divided by the shorter is the golden ratio
Golden ratio multiplier ERG- given a unit segment, this tool creates a circle having a radius equal to the golden ration (useful in the construction of pentagons)
Trisect a segment - This file contains one tool Trisect ERG which trisects the given segment
Parabola Tools
Focus Vertex Parabola ERG - Given the coordinate axes, the focus (F) and the vertex (V), this tool will construct the Parabola specified by these points. The tool will also show the coordinates of the focus and vertex and the equation of the directrix.
Special Circles
9 Point Circle Tool - Given a triangle, this tool will construct the nine point circle.
Tangent Circles - Given two circles and a point on one of the circles, this tool constructs two circles which are tangent to both the first circle at the given point and the second circle.