Which kind of dimension is measured between an extension line and a center line?

The correct answer is related to the concept of "location" dimensions in technical drawing and engineering. Location dimensions are vital as they indicate the positioning of features relative to one another. In this case, measuring the distance between an extension line and a center line serves the purpose of pinpointing the precise location of a feature.

This measurement ensures that components are placed accurately and can be crucial for the assembly process, as it establishes how features like holes, slots, or other elements are aligned concerning a reference point, which is often indicated by a center line. Center lines typically denote symmetry or the center of circles and arcs, making them essential for understanding the layout of a design.

In contrast, size dimensions typically refer to the physical size of a feature itself (like length, width, or height), while reference dimensions do not have any tolerance and serve more as informational values rather than defining a feature's placement within a design. Profile dimensions relate to the contour or shape of a part, further distinguishing it from the concept of location. Thus, focusing on the measurement between the extension line and center line is fundamentally about determining the location of a drawing’s features.