A puzzle piece, in the shape of a triangle, has perimeter 30 cm. Two sides of the triangle are each twice as long as the shortest side. Find the length of each side. what is the length of the congruent sides in cm

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.