4.4 The Ford circles 129
The Geometer’s Sketchpad
Basic commands
- Construct points, segments, lines, circles.
- Construct a segment, ray, or line through two specified points.
- Construct a circle given its center and a point on it. Construct a
circle given its center and radius. - Construct the intersection of two objects.
- Construct the midpoint of a segment.
- Given a lineand a pointP, construct lines perpendicular and par-
allel tothroughP. - Translate, rotate, and dilate.
- Hide an object. (If the sketch you are making becomes too compli-
cated, you may wish to hide some of the objects to make it simpler.
Note that this isnotthe same as “delete”). - Label an object. Change the name of the object.
- Save a Sketch.
- Create New Tool.
Toolbox
Open anew sketch.Selecta segment and build an equilateral triangle
on it. Hideeverything except the vertices and sides of the equilateral
triangle.Selecteverything by dragging the mouse from top left to bot-
tom right. SelectCreate New Tool, and type a name for the tool, say,
equilateral triangle. A new tool will now appear.
Savethis as a filebasic shapes.gspin the foldertool folder.
From theFile menu, chooseDocument options,Add page,Blank
page. On this blank page, construct a square on a segment. Select
Create new tooland name thissquare.Savethe file.
You can extend thisbasic shapes.gsptool by opening new blank
pages and creating new tools. Remember tosavethe file.
The currentbasic shape.gspfile contains the following tools: equi-
lateral triangle, square, rectangle, right triangle, parallelogram, rhombus.
You may of course add your own tools to the same file.