How many known positions are preferable when determining the location of an unknown point using intersection?

Using three known positions is preferable when determining the location of an unknown point using intersection because it provides the most accurate determination of that point's location. The method of intersection involves taking measurements or bearings from known points to an unknown location.

With just one known position, you would only have a single line or direction that the unknown point could potentially lie along, leading to ambiguity in its exact location. With two known positions, you can narrow down the location to two possible points where the lines intersect, but this still does not provide a definitive fix on the exact location.

However, when you utilize three known positions, you create a refined intersection point where all three measurements converge. The intersection of these three lines allows for error correction and increases the reliability and accuracy of the determined position. This method accounts for potential inaccuracies in measurement and helps to pinpoint the unknown location more effectively.