Example 1
Change 3.5 m into centimetres.
- There are 100 cm in 1 m.
- Centimetres are smaller than metres, so multiply by 100.
- 3.5 × 100 = 350
So: 3.5 m = 350 cm
Back to National 4
Topic
Measurement
Measurement questions use units, conversions, scale drawings, perimeter, and sensible accuracy in practical situations.
Topic explanation
Always check the unit before calculating. A correct number with the wrong unit can still be wrong.
For conversions, multiply when moving to a smaller unit and divide when moving to a larger unit.
Scale drawings use a fixed relationship between drawing length and real length. Apply the same scale every time.
Quick methods
- Length
- 100 cm = 1 m and 1000 m = 1 km
- Mass
- 1000 g = 1 kg
- Capacity
- 1000 ml = 1 litre
- Perimeter
- Add all outside lengths.
Worked examples
Example 2
A rectangle is 8 cm long and 5 cm wide. What is its perimeter?
- Perimeter means the distance around the outside.
- Add all four sides: 8 + 5 + 8 + 5.
- 8 + 5 + 8 + 5 = 26
So: The perimeter is 26 cm.
Example 3
On a scale drawing, 1 cm represents 4 m. A wall is 6.5 cm on the drawing. What is the real length?
- Each 1 cm on the drawing stands for 4 m in real life.
- Multiply the drawing length by 4.
- 6.5 × 4 = 26
So: The real wall length is 26 m.