If the sales tax in your city is 10.8%, and an item costs $191 before tax, how much tax would you pay on that item? round to the nearest hundredth or cent.

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.