Analyze Math
Analyze Math: Reflection Across a Line
Reflect any point, line segment, triangle, or any other figure over one or two lines using this dynamic applet. Points and lines are entered by point-and-click rather than by typing equations or ordered pairs. A very neat exercise to...
Illustrative Mathematics
Illustrative Mathematics: G Co Fixed Points of Rigid Motions
A rigid motion of the plane is a map of the plane to itself which preserves distances between points. The purpose of this task is to use fixed points as a tool for studying and classifying rigid motions of the plane, i.e., translations,...
Illustrative Mathematics
Illustrative Mathematics: G Co Seven Circles Ii
For this task, seven pennies are placed in a circle so that they are all touching one in the center and their neighbors. Students are asked to find as many rigid motions of the plane as they can which are symmetries of this configuration...