Sorry Hans, my only trick is Thales intercept theorem. [;)]
Let me explain: as all your walls have the same slope, you can compute easily the height difference between the start point and the end point of each wall.
The sloping wall at left has a length of 1230 cm and a height difference of 200 cm, right?
If you divide 1230 by 200, you get a "slope factor" of 6.15.
Since the next sloping wall at left has a length of 305 cm, its height difference should be
305 / 6.15 = 45.6 cm
If the height of its start point is 500, the end of its end point will be
500 - 45.6 = 450.4 cm