Which line is used to indicate the center of symmetry for arcs and circles?

Which line is used to indicate the center of symmetry for arcs and circles?

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

Answer: (B)

Center lines are the line type used to mark centers and symmetry in engineering drawings. They pass through the center of circles and arcs and show the axis of symmetry, and are drawn with alternating long and short dashes so they stand apart from other lines. This distinguishes them from extension lines, which extend dimension lines from the object, dimension lines, which show measurements, and object lines, which are the visible edges of the part. Because this line is specifically used to indicate the center of a circle or arc, it is the best choice for showing the center of symmetry.

Center lines are the line type used to mark centers and symmetry in engineering drawings. They pass through the center of circles and arcs and show the axis of symmetry, and are drawn with alternating long and short dashes so they stand apart from other lines. This distinguishes them from extension lines, which extend dimension lines from the object, dimension lines, which show measurements, and object lines, which are the visible edges of the part. Because this line is specifically used to indicate the center of a circle or arc, it is the best choice for showing the center of symmetry.