What are extension lines used to connect?

Extension lines are utilized to bridge the dimension line to the specific feature of an object being measured. This connection is crucial in technical drawings because it clearly indicates what part of the object the dimensions refer to. By extending from the outline of the drawing to the dimension lines, these lines provide unambiguous visual cues that help in accurately interpreting the measurements. This clarity is essential for effective communication in engineering and manufacturing processes, ensuring that the dimensions are easily understood in relation to the feature they are describing.

The other options, while involving aspects of technical drawing, do not accurately describe the primary function of extension lines. They either refer to connections between different objects or dimensions related to specific geometric features that do not pertain to the explicit role of extension lines.