Okay, so we know that the perimeter of the square is 20. Since a square has 4 equal sides to find the length of one side, 20/4. Each side is equal to five. Look at each of the coordinates and put them respectively into a graph in your mind. w(3,2) (bottom left) x(3,7) (top left) Y(8,7) (top right). Now we know we need to find the bottom right coordinate. Being that both of the coordinates on the left have the same x value we can justify that the coordinates on the right have the same X value also. we can say this same thing for the y coordinate. Since both coordinates on the top of the square have the same Y value, we can justify that the coordinates on the bottom have the same Y value. So taking the coordinates we now are the same, the answer is Z(8,2). We can check his by seeing if the distance if five from each of the adjacent coordinates. If you have any questions comment below.