SOMEONE PLEASE HELP ME WITH THIS AND FIND THE SURFACE AREA FOR THE FIGURE BELOW

What is the nth term rule of the linear sequence below? 27 , 25 , 23 , 21 , 19 , . .

What is the slope simplify your answer and write it as a proper fraction, improper fraction, or integer

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.