Measurement and scale drawings
OCR J560 Foundation tests basic measurement of lines and angles, scale drawings, bearings, and reading from maps.
Measuring lines
Use a sharp pencil and a clear ruler. Place the 0 mark exactly on one endpoint and read off the other endpoint. Estimate to the nearest mm.
Measuring angles
Use a protractor with the centre on the vertex and the baseline along one of the rays. Read off the angle on the correct scale (inner or outer) — choose the scale that starts at 0 along your baseline.
- Acute: between 0° and 90°.
- Right: exactly 90°.
- Obtuse: between 90° and 180°.
- Reflex: between 180° and 360°.
Scale drawings
A scale of 1 : n means 1 unit on the drawing represents n units in real life. Examples:
- Scale 1 : 100 — 1 cm represents 100 cm = 1 m.
- Scale 1 : 50,000 — 1 cm represents 50,000 cm = 500 m = 0.5 km.
To go from drawing to real life: multiply by n. To go from real life to drawing: divide by n.
Bearings
Bearings are measured from North, clockwise, as a 3-digit angle from 000° to 360°.
- North: 000°
- East: 090°
- South: 180°
- West: 270°
- North-East: 045°
To find the bearing of B from A:
- Stand at A facing North.
- Turn clockwise until you face B.
- Read off the angle.
✦Worked example
A map has scale 1 : 25,000. Two villages on the map are 7 cm apart.
Real distance = 7 × 25,000 = 175,000 cm = 1750 m = 1.75 km.
OCR mark scheme conventions
- B1 for the correct measurement (within tolerance, usually ±2° for angles, ±1 mm for lengths).
- M1 for the scale-factor calculation.
- A1 for the answer with units.
- Bearings must always be 3-digit form (e.g. 070°, not 70°).
⚠Common mistakes
- Using the wrong scale on the protractor (inner vs outer).
- Forgetting the leading zero on a bearing (e.g. 70° should be 070°).
- Measuring bearings from East or anticlockwise (must be from North, clockwise).
- Not converting cm to km when the map scale crosses unit boundaries.
AI-generated · claude-opus-4-7 · v3-ocr-maths-leaves