opposite sides are congruent opposite angles are congruent the diagonals of a parallelogram bisect each other Standard G CO 11 EXPLORE Read the section below and complete the following activity adapted from Lesson 9 1 A quadrilateral is a polygon with four sides A parallelogram is a quadrilateral that has two pairs of parallel sides L4L Math Resources http bit ly L4LMath Proving the Opposite Sides Criterion for a Parallelogram Draw and explain in your own words the following polygons Make sure to use tick marks to label congruent sides and arrows to label parallel sides Definition of a Quadrilateral Definition of a Parallelogram