#### Answer

$R: (0,0) \\ U: (0,a) \\ T: (0,a+b) \\ S:(a,-b)$

#### Work Step by Step

We know that any vertex on the x-axis has a y coordinate of 0, and we know that any coordinate on the y-axis has a x coordinate of 0. Thus, we write 0 where appropriate. We know that any variables with the same height share a y-value, and any coordinates that are separated by a vertical line share an x value, so we fill in more blanks. Next, we see that U has the same height as the x-value of point S. so we see that U has a y coordinate of a. Finally, T has a height equal to the height of U plus the distance S is below the x-axis, giving T a y-value of: a+b. Thus, we find:
$R: (0,0) \\ U: (0,a) \\ T: (0,a+b) \\ S:(a,-b)$