Geometric construction tools: A line drawn perpendicular to a horizontal reference line can only be constructed with a 45° triangle. Judge this claim.

Introduction / Context:Drafters use set squares (triangles), T-squares, parallel edges, and drafting machines to produce perpendicular and parallel lines. This question probes practical knowledge of which tools can create perpendiculars.

Given Data / Assumptions:

• Common set squares: 45°–45°–90° and 30°–60°–90° triangles.
• Reference edges include a T-square, parallel straightedge, or drafting machine rulers.
• The statement limits the method to a single triangle type (45°) for constructing a perpendicular to a horizontal line.

Concept / Approach:Any set square with a right angle (90°) can generate a perpendicular when used against a true horizontal reference (T-square, parallel edge). Both common triangles have a right angle and therefore can produce perpendiculars.

Step-by-Step Solution:Place a T-square or parallel edge to establish the horizontal reference.Align either a 45° or a 30°–60° triangle so that its right-angle vertex sits on the line to be drawn.Draw along the leg that is perpendicular to the horizontal edge.Therefore, a 45° triangle is not the only viable tool; any right-angle triangle or a drafting machine can create the perpendicular.

Verification / Alternative check:Demonstrations in drafting manuals show perpendiculars made with both triangle types, as well as with the protractor head on a drafting machine set to 90°.

Why Other Options Are Wrong:“Correct” contradicts the existence of the 30°–60° triangle. The other options add irrelevant conditions (paper taped, vellum thickness) or misapply the T-square requirement.

Common Pitfalls:Assuming “45° triangle” is synonymous with “right triangle.” Both common triangles include a 90° angle; the exact acute angles only affect other constructions.

Final Answer:Incorrect