So, I know a few players seemed confused on this, so I thought I'd explain it:

Angle of Depression is the same as the angle acrossed from it (angle of elevation in this case) So for example if the bottom right angle was 35 degrees than the upper left angle would also be 35 degrees. Using this, you could calculate that the bottom right angle is 145 degrees as well as the upper right angle would be 145 degrees. (Since a straight line is 180 degrees, 180-35=145)

omg. I thought you meant depression as in the mental affliction