Explanation:
"A parallelogram has one pair of parallel sides."
False. A parallelogram has two pairs of parallel sides.
"If a quadrilateral is a rectangle then it is also a square."
False. A rectangle isn't necessarily a square. Rectangles are only squares when all four sides are equal.
"A parallelogram always has four congruent sides."
False. Parallelograms have two pairs of congruent sides. All four sides aren't necessarily congruent.
"If a quadrilateral is a square then it is also a rectangle."
True. All squares are rectangles.
"If a quadrilateral is a trapezoid then it is also a parallelogram."
False. Trapezoids have only 1 pair of parallel sides, and parallelograms have 2 pairs of parallel sides.