premise: How to use a graphic flight computer to find ground speed and true heading<br>Align the wind direction under the " true index " mark by rotating the azimuth plate. If the winds are from 330 ° at 20 knots, align 330 under the true index. Align the grid so the center grommet is over one of the heavy lines.
hypothesis: ground speed and true heading can are best found with a graphic flight computer
reason: The context only states it is a way to do measure flight speed, not that is the best. There might be a better method. The system could likely not interpret the use of the word best as meaning the top method. 