In an experiment to determine whether the amount of coverage of a specific new kind of protecting coat of a thin film for the food industry depends either on the process of applying the film or the worker experience, 1 gallon for each of four processes was applied and three workers with different experience were considered, resulting in the following data (Squared feet covered).

If m∠abc = 70°, what is m∠abd? justify your reasoning.  using the addition property of equality, 40 + 70 = 110, so m∠abd = 110°.  using the subtraction property of equality, 70 − 30 = 40, so m∠abd = 30°.  using the angle addition postulate, 40 + m∠abd = 70. so, m∠abd = 30° using the subtraction property of equality.  using the angle addition postulate, 40 + 70 = m∠abd. so, m∠abd = 110° using the addition property of equality.