QUADRILATERALS | SUFFICIENT CONDITION FOR A QUADRILATERAL TO BE A PARALLELOGRAM, PROPERTIES OF A RECTANGLE; RHOMBUS AND SQUARE | A quadrilateral is parallelogram if its opposite sides are equal, A quadrilateral is parallelogram if its opposite angles are equal., If the diagonals of a quadrilateral bisect each other, then the quadrilateral is a parallelogram., A quadrilateral is parallelogram, if its one pair of opposite sides are equal and parallel, Each of the four angles of a rectangle is a right angle., Each of the angles of a square is a right angle and each of the four sides is of the same length, If the two diagonals of a parallelogram are equal, it is a rectangle.