Geometry JavaScript Applet Gallery

Saltire's Geometry Gallery is a collection of JavaScript applets showing interesting geometry configurations.  All applets are dynamic in that user input can cause the configuration to change.  In some cases, points can be dragged.  In other cases dimensions can be changed via edit controls.  Some of the applets feature animation.

Basic Geometry

Applets in this gallery exhibit basic geometrical properties of angles in parallel lines and circular configurations. We also look at pythagorean triples and incircles.

Advanced Geometry

A number of advanced geometrical configurations are presented. These cover theorems about common tangents to circles, Napoleon's theorem on the incenters of equilateral triangles and a number of textbook problems as well as an illustration of Casteljeau's spline construction algorithm.

Some Student Apps

Apps created by students using geometry Expressions 3.0

Triangle Calculators

Four triangle calculators are presented, which allow for the triangle to be specified either by three sides, two sides and the included angle, two sides and the non-included angle or two angles and one side. In all cases the remaining sides and angles are computed.


Four bar, six bar, and Peaucellier's straight line mechanism are illustrated.


Our Cam design apps let you enter the follower function and create a cam profile. Reciprocating and oscillating flat face and roller followers.