If quadrilateral is reflected across the line , what are the vertex coordinates of quadrilateral ? Graph shows a four-sided polygon plotted on a coordinate plane. The polygon is at A (0, 1), B (4, 1), C (2, 4), and D (2, 2). Type the correct answer in each box. Use numerals instead of words. For help, see this worked example. : ( , ) : ( , ) : ( , ) : ( , )