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.