I need help with this

Me, the vertices of quadrilateral coat are c(2,0), o(7,0), a(7,2) and t(2,2). prove that coat is a rectangle.

Suppose you just purchased a digital music player and have put 8 tracks on it. after listening to them you decide that you like 4 of the songs. with the random feature on your player, each of the 8 songs is played once in random order. find the probability that among the first two songs played (a) you like both of them. would this be unusual? (b) you like neither of them. (c) you like exactly one of them. (d) redo () if a song can be replayed before all 8 songs are played.

How can you find the mean absolute deviation (mad) for this set of data?