a wheel ramp must form angle no greater than 4.8 degrees with the ground. If a 1.8 foot high ramp is needed, what is the maximum horizontal length for the ramp so it satisfies the angle requirement? Include a sketch of the ramp!!!

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.