Which two measurements are necessary to determine the true length of an element line when triangulating from a plan view?

To determine the true length of an element line when triangulating from a plan view, the necessary measurements are plan length and elevation height. The plan length provides the horizontal distance of the element as viewed in the plan, while the elevation height allows for understanding the vertical aspect of the element. Using these two measurements together enables the application of the Pythagorean theorem to calculate the true length, accounting for both dimensions in a three-dimensional space.

In triangulation, it is crucial to have both horizontal and vertical components to arrive at an accurate representation of the line's length. This foundational approach is important for accurate sheet metal fabrication and installation, where precise measurements are necessary for proper fit and function. Other combinations of measurements do not provide both necessary dimensions or do not relate correctly to the concept of true length.