Transformations and Symmetry Practice Test

A new shape is created by joining two congruent right isosceles triangles along their longest sides (hypotenuses). Which statement best describes the symmetry of the resulting quadrilateral?

A certain polygon is known to have at least one pair of parallel sides. It is also known to have rotational symmetry of 180 degrees. Based on this information, which of the following must be true about the polygon?