Suppose 75 tagged rainbow trout were released into the Lower Saluda River below the Lake Murray Dam. Fishermen reported catching 10, 30, and 80 rainbow trout. Based on the number of tagged fish caught, find the estimated population and enter the results below. Then find the percent error estimated population and enter the results below. Then find the percent error.

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.

What is the the greatest common factor ?

Find the interior angle of a regular polygon which has 6 sides