What is the mean of 12, 24, 24, and 52

In the final round of trivia competition, contestants were asked to name as many states that begin with the letter m as they could in 15 seconds. the bar graph shows the number of states the contestants were able to name. how many contestants participated in the final round of the competition?

If you answer right ill give brainliest, : )

Anna is constructing a line segment that is congruent to another segment ab. for the construction, which tool should be used to mesure segment ab