Priya is playing a game where she earns online badges for scoring higher than the mean score on a level. After the tenth level, she scores 3,540 points, which is 2 standard deviation above the mean score of 3,110 points. What is the standard deviation of scores for the tenth level?

Which statement explains how you could use coordinate geometry to prove the opposite sides of a quadrilateral are congruent? a. use the slope formula to prove the slopes of the opposite sides are the same. b. use the slope formula to prove the slopes of the opposite sides are opposite reciprocals. c. use the distance formula to prove the lengths of the opposite sides are the same. d. use the distance formula to prove the midpoints of the opposite sides are the same.