We just need to show that the midpoint of each diagonal is the same point. We find the midpoint of the diagonal connecting (-1,1) and (4,1) Midpoint =Midpoint = Midpoint = Midpoint = We find the midpoint of the diagonal connecting (0,-3) and (3,5) Midpoint = Midpoint = Midpoint = Midpoint = Since the two diagonals have the same midpoint, they bisect each other. Edwin