Describe Geometry Construction Set

In GeoCnstr, you draw:

Then, view information, e.g., perimeter, area, or perform operations, e.g., inscribe circle, bisect side.

Keywords: education, learning, geometry, construction

Use GeoCnstr

Tap i:Help to view this document as an embedded help book

Draw a line segment, rectangle, square, triangle, circle.

Select an "interesting point" (small square), e.g., vertex, midpoint, to popup information about an object and perform operations, which add "annotations".

Select/(tag)drag to (copy)move/reshape an object. Scrub to erase: annotations (2.x: if any), then object.



A LineSeg displays its midpoint and two endpoints.

Note: currently, y coordinates increase from top to bottom.


A Rectangle displays:


A Square is basically a rectangle with equal sides, with several additional items:


A Circle displays its center:

and a point on the circle:



A Triangle displays many points. For best results, try to make it large and/or non-symmetric. A vertex displays:


A side displays its midpoint:


A triangle has several "centers":


Draw a large, asymmetric triangle.

Select midpoint of each side and bisect; intersection is circumcenter; select circumcenter to draw a circumcircle. Scrub triangle once to erase annotations.

Bisect each angle, draw incircle.

Add Medians from each vertex; intersection is centroid.

Add Altitudes from each vertex; intersection is orthocenter.

GeoCnstr Versions

NewtonScript version of GeoCnstr is based on Smalltalk code for learning environments I wrote in the mid-'1970s .

GeoCnstr created with NewtDevEnv; it's 1.x/2.x compatible. Help book created from HTML by Newt's Cape.

Version 1.0 (11 Mar 1998)
Future: I may add other operations, objects (trapezoids, ellipses). Implement as stationery?

Distribute GeoCnstr

GeoCnstr is freeware, and may be distributed freely as long as all of the files are included and unmodified.

I may make GeoCnstr source available to registered NewtDevEnv users.

© Copyright 1997-98, S. Weyer. All Rights Reserved Worldwide.

Contact Author

Steve Weyer
17 Timber Knoll Drive
Washington Crossing, PA 18977-1052
America Online, Compuserve: SteveWeyer