#$&* course Phy 231 Using geometrical rearrangements, we can find the area of a trapezoid. In the case of the trapezoidal area underneath the line connecting the two points on our V-t graph, this area equals (delta t)(V_0 + V_f)/2. This area can be interpreted as the change in position over the time interval t_0 to t_f.These area calculations remain correct to the extent that the actual velocity resembles our straight line between our points.