Final answer:
A trackman should always know the precise, straight-line distance between two points on the track for accurate measurement of track and field events.
Step-by-step explanation:
A trackman, who is responsible for maintaining and managing a track and field facility, should always take the precaution of knowing the precise, straight-line distance between two points on the track. This is important for accurate measurement of events such as races, long jumps, and throws.
To ensure accurate measurements, trackmen often use a surveying tool called a measuring wheel or a steel tape. They start at one point on the track, walk along the straight line, and measure the distance from start to finish. By doing so, they can ensure fair competition and accurate records in track and field events.
For example, in a 100-meter race, it is crucial that the trackman measures the 100-meter distance accurately to provide a level playing field for all athletes and to ensure that race times are comparable.