Dimensioning convention: when two lines meet at a right angle in a drawing, it is standard practice to omit the angular dimension at which angle value because it is assumed by default?

Introduction / Context:
Drafting standards promote clarity by dimensioning only what is necessary to define the part. Redundant or obvious dimensions are omitted to reduce clutter and prevent conflicting information.

Given Data / Assumptions:

• Two lines intersect at a right angle (orthogonal geometry).
• Standard orthographic drawing practices are followed.
• We want to know which angle is conventionally not dimensioned.

Concept / Approach:
Right angles are inherently assumed where edges are drawn perpendicular unless a non-right angle is required. By not dimensioning 90 degrees, the drawing stays clean, and attention is drawn to nonstandard angles which must be explicitly called out.

Step-by-Step Solution:

Verification / Alternative check:
Check ASME or ISO dimensioning practices: only non-orthogonal angles are typically dimensioned; square symbols or notes may be used where needed.

Why Other Options Are Wrong:

• 360: A full rotation; irrelevant to edge intersections.
• 180: A straight line; not an intersection angle between two distinct edges.
• 45: Often dimensioned explicitly for chamfers or miters.

Common Pitfalls:
Failing to indicate when a corner is not square; if a surface requires a draft angle (e.g., molded parts), explicitly dimension the non-90-degree value.

Final Answer:
90