the formula for the volume of a cylinder is v = πr2h, where v is the volume, r is the radius, and h is the height. solve the formula for r, and then use it to answer the question. a cylindrical bucket contains 615 cubic inches of water. the height of the water is 4 inches. what is the radius of the bucket, to the nearest whole number? use 3.14 for π.

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.