All of the statements are correct. Squares and Parallelograms are quadrilaterals as they both have 4 sides each. Opposite sides of Squares and a Parallelograms are parallel as the two lines never meet even if they go on forever. A Trapezoid only has one pair of parallel sides as the of the other pair of sides if extended, will eventually meet each other. Meaning that a Trapezoid only has one pair of parallel sides.