If a coin tossed 300 times .Then the nearest expected number for the tail to appear is

Which expression is not a polynomial?

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.

Which of the following represents the length of a diagonal of this trapezoid?