Prove a quadrilateral with vertices g(1,-1), h(5,1), i(4,3), j(0,1) is a rectangle

parallelogram method:
rectangle method:

i need understanding how to prove it's a rectangle

!! 10 ! a westbound jet leaves central airport traveling 635 miles per hour. at the same time, an eastbound plane departs at 325 miles per hour. in how many hours will the planes be 1900 miles apart?

There are 45 questions on your math exam. you answered 810 of them correctly. how many questions did you answer correctly?

There are three bags: a (contains 2 white and 4 red balls), b (8 white, 4 red) and c (1 white 3 red). you select one ball at random from each bag, observe that exactly two are white, but forget which ball came from which bag. what is the probability that you selected a white ball from bag a?