Arectangular prism has a volume of 16cm^3 and a total surface area of 40cm^2. a similar prism has length 10 in., width 5 in. and height 5 in. what are the dimensions of the original prism? length= width= height=

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.