Jen buys 4 tires for$272 what is the cost of one tire

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.

Collin did the work to see if 10 is a solution to the equation r/4=2.4

The triangles are similar. what is the value of x? enter your answer in the box.