standard_description: Use special triangles to determine geometrically the values of sine, cosine, tangent for π/3, π/4 and π/6, and use the unit circle to express the values of sine, cosines, and tangent for π–x, π+x, and 2π–x in terms of their values for x, where x is any real number.
problem_activity: Task
Rhianna has learned the SSS  and SAS congruence tests for triangles and she wonders if these tests might work for parallelograms.
Suppose $ABCD$ and $EFGH$ are two parallelograms all of whose corresponding sides are congruent, that is $|AB| = |EF|, |BC| = |FG|, |CD| = |GH|,$ and $|DA| = |HE|$.  Is it always true that $ABCD$ is congruent to $EFGH$?
Suppose $ABCD$ and $EFGH$ are two parallelograms with a pair of congruent corresponding sides, $|AB| = |EF|$ and $|BC| = |FG|$.  Suppose also that the included angles are congruent,
$m(\angle ABC) = m(\angle EFG)$.  Are $ABCD$ and $EFGH$ congruent?


aligns: no