EUKLID DynaGeo 

EUKLID DynaGeo is a program that can create dynamic geometrical drawings. You can move certain objects in the drawing without destroying any of the geometrical interdependencies between the objects, which were there when you constructed them originally. So if you have managed to draw a circle passing through all the points of a triangle, then even if you move the edges of the triangle around, still the circle will pass through the three points of the triangle. You can draw all the regular geometrical shapes and objects with this program. There are built-in standard objects like perpendicular, bisector and so on, which you can use in your constructions. Certain mapping elements are also built-in, for example, reflection, rotation and so on. With this program you can measure the widths of your angle and also distances in your drawings. Coloring of different objects in your construction is also possible. If you are an advanced user, you can do trace lines, which can also be dynamic. Incorporate macros into your drawings so that your detailed constructions, will not be a lengthy affair. The program enables you to copy what you have created into an EMF or BMP format onto the clipboard. Your dynamic constructions can be exported onto a web page.