A swimmer dives off the edge of a cliff. The distance, d(t), in meters, the swimmer travels after
t seconds can be modeled by the function d(t)=0.5t^2. What is the average speed, in meters
per second, of the rock between 3 and 8 seconds after she dived? *

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.