What's the reciprocal of 1/7

The fence around a quadrilateral-shaped pasture is 3a^2+15a+9 long. three sides of the fence have the following lengths: 5a, 10a-2, a^2-7. what is the length of the fourth side of the fence?

David leaves his house to go to school. he walks 200 meters west and 300 meters north. how far is david from his original starting point?

Of the 27 players trying out for the school basketball team, 8 are more than 6 feet tall and 7 have good aim. what is the probability that the coach would randomly pick a player over 6 feet tall or a player with a good aim? assume that no players over 6 feet tall have good aim. a. b. c. d.