The unpaid balance on a mastercard charge was $1,056.23. during the month, payments of $300 and $250 were made and charges of $425 and $274.16 were added. if the finance charge is 1.2% per month on the unpaid balance, find the new balance at the end of the month. $1,205.39 $1,218.06 $918.06 $1,768.06

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.