Find a pair of square numbers which give a difference of 39

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.

Tom drove 206 miles in 3.9 hours. estimate his average speed.

The perimeter of a rectangular rug is 24 feet. the length of the rug is 1 2/5 i s width. what is the area of the rug