Unfortunately, Mark’s share of GUAC stock lost another $20.88 in value each month for the next 3 months. If the previous share price of GUAC was $348, and the stock lost an equal amount each month, what was the average percentage change each month?

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.