Which line represents where a dimension starts and stops?

Which line represents where a dimension starts and stops?

• A. Center Line
• B. Extension Line
• C. Dimension Line
• D. Hidden Line

Answer: (B)

In an engineering drawing, the line that marks where a dimension starts and stops is the extension line. Extension lines start at the feature on the object and extend outward to meet the dimension line, showing exactly which points the measurement covers. They define the extent of the dimension, while the dimension line itself carries the arrows and the numeric value of the measure. The other lines have different roles: center lines indicate symmetry or axes, and hidden lines show features not visible in the view. So extension lines are the ones that define the boundaries of the dimension.

In an engineering drawing, the line that marks where a dimension starts and stops is the extension line. Extension lines start at the feature on the object and extend outward to meet the dimension line, showing exactly which points the measurement covers. They define the extent of the dimension, while the dimension line itself carries the arrows and the numeric value of the measure. The other lines have different roles: center lines indicate symmetry or axes, and hidden lines show features not visible in the view. So extension lines are the ones that define the boundaries of the dimension.