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: Rotate the following figure
$${90^{\circ}}$$
counterclockwise about the origin, three times.
[IMG]
A shape is formed through these rotations, with center at the origin.
Does this shape have rotational symmetry? If so, by what order/degree?
Doe this shape have reflectional symmetry? If so, what is the line of symmetry? If not, describe why not.


aligns: yes