Creating a 15° line with drafting triangles A 15° line can be produced by combining the standard 45° triangle with the 30°/60° triangle. Evaluate this statement.

Difficulty: Easy

Correct Answer: Correct

Explanation:


Introduction / Context:
Traditional drafting uses fixed-angle triangles (45° and 30°/60°) with a T-square or straightedge to construct common angles. Combining these aids enables many additional angles without a protractor.



Given Data / Assumptions:

  • A 45°-45°-90° triangle and a 30°-60°-90° triangle are available.
  • Triangles can be stacked or used against a straightedge without slipping.
  • Desired output is a 15° line relative to a reference horizontal.


Concept / Approach:
Using angle subtraction: 45° - 30° = 15°. By orienting one triangle against the other, the composite angle between a triangle edge and the baseline becomes 15°, allowing accurate construction of that angle.



Step-by-Step Solution:

Place the 45° triangle base against the straightedge to establish a stable reference.Slide and rotate the 30°/60° triangle against the 45° to achieve a relative 15° edge.Draw along the exposed 15° edge to create the desired line.Repeat as needed, keeping contact between triangles to preserve alignment.


Verification / Alternative check:
Many drafting texts list standard composite angles achievable with triangles, including 15°, 75°, and others derived from sums/differences of 30°, 45°, and 60°.



Why Other Options Are Wrong:
“Incorrect” would suggest the triangles are limited to only their nominal angles; in practice their combination yields additional precise angles.



Common Pitfalls:
Slippage between triangles leading to angle error; misidentifying the 30° versus 60° side; forgetting to keep one edge firmly against the baseline.



Final Answer:
Correct

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