Task# Triangle congruence with coordinates

Illustrative MathematicsVaries

This task gives students a chance to explore several issues relating to rigid motions of the plane and triangle congruence. First, part (a) gives students an opportunity to describe rigid motions in the coordinate plane to exhibit a congruence between two explicit triangles. There are two reasons to ask students to first find a reflection followed by a translation that will show the congruence. One is that there are multiple combinations of reflections followed by translations that will work, giving students a chance to see that there is more than one way to do this.