m∠DAB can be determined by looking at the angle on the opposite side. The box indicates that it is a 90° angle, and any straight line is inherently 180. m∠DAB is a supplementary angle to the angle on the right, so it must add with the 90° to make 180°. So, m∠DAB is 180 - 90, which is 90, so m∠DAB is 90°.
∠DAC is a complementary angle to ∠BAC, which means when added up together they are 90°, so if you want ∠DAC, you will have to take away ∠BAC from the right angle. m∠DAC = 90 - 56 = 34. Thus, m∠DAC is 34°.