To calculate each of these rates we simply calculate the slope between each set of points using the values from the table
a) For 12:44:00 the point is (60,1276) and 12:45:00 the point is (120,2520). Using the slope formula we have
We interpret this as an average rate of 20.73 m/s which converts to 74.6 km/h
b) For 12:44:15 the point is (75,1668) and 12:44:45 the point is (105,2390). Using the slope formula we have
We interpret this as an average rate of 24.07 m/s which converts to 86.65 km/h
c) For 12:44:25 the point is (85,1928) and 12:44:35 the point is (95,2193). Using the slope formula we have
We interpret this as an average rate of 26.5 m/s which converts to 95.4 km/h
d) From this progression we could estimate the slope of the tangent or the speed at 12:44:30 to be approximately 97 km/h