What shape does the profile line symbol have?

• A. A semicircle arc
• B. A straight line
• C. A triangle
• D. A square

Answer: (A)

The profile line symbol is represented by a semicircle arc. This unique shape is specifically designed to distinguish the profile tolerance from other geometric tolerances and indicates a controlled form, contour, or outline that could be applied to a feature on the part.

The semicircle symbol conveys that the tolerance applies to the entire profile or outline of a shape, allowing for variations while ensuring that the overall contour remains within defined limits. This visual representation helps manufacturers and quality control personnel quickly identify the requirement for the profile tolerance on technical drawings. Other shapes listed do not correspond to the standard symbol used to indicate profile tolerances in geometric dimensioning and tolerancing (GD&T) standards, thus serving different purposes or meanings in the context of engineering drawings.