Shayan brought her computer into a shop for repairs. When she came back to pick up her computer, she was given a bill for 280. Shayan was angry because the technician made a few repairs that they had not agreed upon in advance. Shayan and the computer repair shop ultimately agreed on a final bill that was 25% lower than the initial bill. What was the amount of the revised bill?

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.