Since line AB = 5*sq root of 2, that tells us triangle ADB is an isoceles right triangle with legs=5. Therefore, triangle ACD is also an isoceles right triangle and so angle ACD (or B) = 45 degrees. One radian = 180/pi or 57.2958. Therefore angle ACB in radians is 45/57.2958 = .7854 = H*Pi. So H = .7854 / Pi = .7854 / 3.14159 = .0.25
