What condition is necessary for A ⁢ E ¯ and B ⁢ F ¯ to be equal? In this situation, what is the relationship between A ⁢ B ↔ and C ⁢ D ↔ ? What can you conclude about parallel lines with regard to the distance between them? Use the word perpendicular in your answer.

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.