A relation is O the output (y) values of the relation
O the input (x) values of the relation
O a set of points that pair input values with output values
Ox and y values written in the form (x, y)

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.