Before drawing, which four settings should be verified in OHMIC CAD?
Answer: Units, sheet size, grid, and snap
Reasoning: These settings control scale and precision.
Reasoning: These settings control scale and precision.
Unit 12 · Lesson 02 · CAD, Scale Drawing & Spatial Design
Precision Lines, Angles and Dimensions · Teacher Key
Report measurement, absolute error, relative error, and appropriate significant figures.
Learning intention
Use accurate diagrams, definitions, measurements, and reasoning to report measurement, absolute error, relative error, and appropriate significant figures.
Success evidence
- Label the figure and units before calculating.
- Select and justify the governing definition, theorem, relationship, or construction.
- Show enough work that another learner can audit the conclusion.
- Check the result against the diagram, scale, and stated constraints.
Visual model
Use a local-first CAD environment to create precise, scaled, layered, measured, and exportable geometric designs.
\text{drawing length}=\text{actual length}\times\text{scale factor}A=lwP=2l+2w
Worked reasoning
Process: Set units and scale, construct with grid and snap, dimension critical objects, verify area and length, then export a print-ready artifact with a design note.
- Read the figure and rewrite all given information with correct notation.
- Identify the exact relationship that connects the known and unknown quantities.
- Substitute, construct, or prove one justified step at a time.
- State the result with units and a sentence explaining what it means.
Misconception check: A visually attractive drawing is not automatically precise; dimensions, scale, units, and constraints must be explicitly verified.
Khaemenes Academy · Open-Age Geometry
Precision Lines, Angles and Dimensions
Find, construct, prove, or explain each result. Show reasoning and label units.
Name
Date
A 1:100 plan shows a 6.5 cm wall. Find the actual wall length.
Answer: 6.5 m
Reasoning: 6.5 cm×100=650 cm=6.5 m.
Reasoning: 6.5 cm×100=650 cm=6.5 m.
Why place dimensions and walls on separate layers?
Answer: They can be controlled, inspected, and exported independently
Reasoning: Layer organization supports editing and technical communication.
Reasoning: Layer organization supports editing and technical communication.
Which export best preserves editable project state?
Answer: Project JSON
Reasoning: JSON is the complete local project format.
Reasoning: JSON is the complete local project format.
Which export is best for sharp vector printing and visible geometry?
Answer: SVG
Reasoning: SVG preserves scalable vector lines and metadata.
Reasoning: SVG preserves scalable vector lines and metadata.
What evidence should accompany a CAD design defense?
Answer: Dimensions, scale, area/length checks, constraints, assumptions, and limitations
Reasoning: A technical drawing must be mathematically auditable.
Reasoning: A technical drawing must be mathematically auditable.