Answer:
Slope of graph
Step-by-step explanation:
The total displacement divided by total time taken by an object is called its velocity. When a position - time (x-t) graph is plotted, the magnitude of velocity is given by its slope.
The slope of position-time graph gives the velocity of an object. The attached figure shows a position time graph.
The slope of this graph is given by :

i.e.
The velocity of this object is 10 m/s. So, to calculate the velocity on an object, the slope of the position vs time graph should be calculated.