25 points! :)

Pretty simple question, just not sure how to do it.

The perimeter of a rectangle is 42 inches. if the width of the rectangle is 6 inches, what is the length

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.

Pls never taught i’m really confused and i rlly need