Answer:
2 units
Explanation:
Polygons are shapes with straight sides and must be closed. Also, polygons sides never touch. Polygons are classified according to its number of sides. Since in this problem we have four points because the polygon is PQRS, then this is a Quadrilateral, which is any polygon with exactly 4 sides. We only know two points P(1, 2) and Q(−1, 2). To find the length of Side PQ of the polygon we must use the distance formula:


Finally, the length of Side PQ of the polygon is 2 units