To find average velocity from a velocity vs. time graph with non-constant acceleration, calculate the area under the graph between the specified time intervals, t1 and t2, which represents the total distance traveled. The average velocity is then determined by dividing this total distance by the total time elapsed, expressed as average velocity = total distance / total time. This method effectively accounts for varying acceleration by focusing on the area under the curve. Understanding this concept is crucial for accurately interpreting motion in physics. The approach provides a clear framework for analyzing average velocity in scenarios involving non-constant acceleration.