Classification — whole : part relation (spot the mismatch): Which pair does not correctly express a whole–part relationship: Circle : Arc, Line : Dot, Hexagon : Angle, Square : Line?

Introduction / Context:
Three options represent standard whole–part compositions in elementary geometry. One option, however, does not match the common “named part” convention for the given whole. The key is to use textbook-level geometric terminology rather than set-theoretic abstractions that might muddy the classification.

Given Data / Assumptions:

• Circle → Arc: an arc is a recognized portion of a circle.
• Hexagon → Angle: a hexagon is composed of six angles (and six sides).
• Square → Line: the boundary of a square consists of four line segments (sides).
• Line → Dot: “dot” is an informal term for a point; standard whole–part phrasing is not “line : dot.”

Concept / Approach:
Match each whole with its conventional geometric part. In school geometry, we describe a line as a straight path with infinite length, typically composed of points in a set-theoretic sense, but we do not label “dot” as a part of a line in the same categorical way we label “arc” as part of a circle or “angle” as part of a polygon.

Step-by-Step Solution:
1) Circle : Arc → valid whole–part.2) Hexagon : Angle → valid whole–part.3) Square : Line → valid boundary-part (line segments).4) Line : Dot → mismatched; “dot” is not the standard named part used in this context.

Verification / Alternative check:
Replace “dot” with “point” and reconsider: even then, exam convention prefers “line segment : point (endpoint)” for part relations; “line : dot” remains ill-posed compared to the other precise terms.

Why Other Options Are Wrong:
They each map a well-known geometric figure to its accepted component.

Common Pitfalls:
Overthinking with abstract set theory (“a line is a set of points”) can mislead. Stick to elementary-geometry naming conventions.

Final Answer:
Line : Dot