Somebody please help me with 19

Select all the correct answers. what is 221,000,000,000,000,000,000 expressed in scientific notation?

Find the average speed of a rabbit that runs a distance of 22 m in a time of 1.8 s .

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.