standard_description: Use the definition of congruence in terms of rigid motions to show that two triangles are congruent if and only if corresponding pairs of sides and corresponding pairs of angles are congruent.
problem_activity: Problem 1
Watch
this video
(without sound). What properties of reflections are being used to reflect each point?
Problem 2
Refelect
$${\angle ABC }$$
over
$${\overleftrightarrow {DE}}$$
using constructions.
[IMG]
Problem 3
Find the line of reflection between the two figures.
[IMG]


aligns: no