While it was true that the cotton gin reduced the labor of removing seeds, it did not reduce the need for slaves to grow and pick the cotton. In fact, the opposite occurred. Cotton growing became so profitable for the planters that it greatly increased their demand for both land and slave labor
In a parallelogram, both pairs of opposite angles are congruent. Also, both pairs of opposite sides are parallel, meaning there are consecutive interior angles. Consecutive interior angles equal 180, so simply subtract 57 from 180 to find your missing angles.