Congruent Figures: Dynamic Illustration

Recall an ISOMETRY is a transformation that preserves distance. So far, we have already explored the following isometries: Translation by Vector Rotation about a Point Reflection about a Line Reflection about a Point (same as 180-degree rotation about a point) For a quick refresher about isometries, see this Messing with Mona applet.


Definition: Any two figures are said to be CONGRUENT if and only if one can be mapped perfectly onto the other using any 1 or composition of 2 (or more) ISOMETRIES. The applet below dynamically illustrates, by DEFINITION, what it means for any 2 figures (in this case, triangles) to be CONGRUENT. Feel free to move the BIG WHITE VERTICES of either triangle anywhere you'd like at any time.

Quick (Silent) Demo