The tabulated distances are in meters, so we need to convert 535 feet to meters. A meter is about 3.28 feet, so the distance the marble falls is 535/3.28 = 163 meters. That distance lies between the table entries for 5.5 and 6.0 seconds, so a reasonable guess about its speed at impact would be the average speed for a falling object between times t = 5.5 and t = 6.0:
`text(change in position)/text(change in time) = (175.8-147.7)/(6.0-5.5) =56.2 text(m/s.)`
In our original units, that would be 184 feet per second, or 126 miles per hour.