Last week, Lamar had $983.45 in his checking account. Since then, he paid $214.67 for his car loan. He also donated $15 to the fire department. Then, Lamar deposited the $50 check his grandma sent him for his birthday. What is Lamar's balance now?

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.