standard_description: Explain how the criteria for triangle congruence (ASA, SAS, and SSS) follow from the definition of congruence in terms of rigid motions.
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: no