Drawing Instruments and Their Uses
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Lesson overview
The core instruments used in technical drawing and the specific purpose of each.
Go to lesson quiz →Exam guidance · WAEC WASSCE Paper 1 + Paper 2 Lens
Pacing
Objective speed on Paper 1 + structured step-by-step method marks on Paper 2 Theory/Practical.
How WAEC marks this
Examiners award method marks (M1) for stating the formula/definition and accuracy marks (A1) ONLY when SI units are written.
Watch out for
Writing bare numbers without working or omitting SI units loses up to 50% of Paper 2 marks even when the final value is right.
Lesson content
Overview — Drawing Instruments and Their Uses
The core instruments used in technical drawing and the specific purpose of each. This lesson is at the beginner level — by the end, you'll be able to recognise this question type, apply a reliable method, and avoid the traps that cost marks.
Key Concept
Technical drawing relies on specific instruments: a T-square and set squares (30°/60° and 45°) for drawing straight and angled lines, a compass for circles and arcs, a protractor for measuring angles, a scale rule for accurate proportional measurement, and a drawing board to which paper is fixed square.
Why It's Tested This Way
WAEC tests knowledge of instruments and their specific uses because accurate technical drawing depends entirely on using the correct tool for each task — a drawing constructed with the wrong instrument (measuring an angle with a scale rule, for instance) cannot achieve the precision the subject requires.
Method
When answering, be ready to match a specific drawing task (drawing a 60° line, measuring an irregular angle, drawing a circle of a given radius) to the correct instrument, rather than only naming instruments in isolation.
Worked Example
Worked example: To draw a line at exactly 30° to the horizontal, a technical drawing student uses a 30°/60° set square against a T-square held firmly against the drawing board's edge, rather than attempting to estimate the angle freehand or with a protractor alone.
Second Worked Example
Second worked example: To draw a circle of radius 40mm, a compass is set to that exact radius using a scale rule for accuracy, then rotated around a fixed centre point — a task a set square or T-square cannot perform, since only a compass can maintain a constant radius through a full rotation.
Common Traps
Common trap: assuming a protractor is used for drawing angles rather than only measuring them — in technical drawing practice, angles are more often constructed precisely using set squares or geometric construction methods, with a protractor primarily used to measure or verify an angle already drawn.
Lesson Summary
Remember: (1) identify what is being asked, (2) apply the WAEC strategy, (3) check against the traps. Complete the 10-question quiz below to unlock the next lesson — you need at least 60% to pass.
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