Well to find the angles, simply see what must the angles be, to equal to 180 or 90 degrees. So we know the angle between C and D would be 90 degrees, so will the angle between A and C. The angle between B and A and the angle between B and C must give us a total of 90 degrees, so that means each would be 45 degrees. As 45 + 45 = 90. Also I would assume that angle between D and F would also be the same as between B and A which would be 45 degrees. Finally the angle between A and F would be the difference between 180 and 45 degrees. So it would be 180 - 45 = 135 degrees.