HELP PLEASE PLEASE

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.

What is the circumference of the pie

Zahra runs a 500-meter race at a constant speed. which graph shows her distance from the finish line during the race?