When working on worded problems involving height, length, and distance, we use units of measurement such as millimetres (mm), centimetres (cm), metres (m) and kilometres (km).
Measuring Distances or Lengths
To measure distances, for example, how tall you are, we can use tools such as a ruler or a tape measure. Watch this video to see how.
Make sure you write the units of measurement at the end of your answers.
E.g. $17$17 cm, not just $17$17.
Converting Distances
We always want to make sure that the measurements we are working with have the same units, like cm, m, mm or km. This means we may need to convert some of the measurements, so that they are all in the same units.
Let's consider a little problem.
Imagine two friends are trying to work out the difference in their heights.
Amelia is $1.44$1.44 m tall. Tran is $130$130 cm tall. How do we work out who is taller and by how much?
Here is a summary of some common distance conversions. These are really important to remember!
| $1$1 cm | $=$= | $10$10 mm |
| $1$1 m | $=$= | $100$100 cm |
| $1$1 km | $=$= | $1000$1000 m |
Make sure that all measurements are in the same units before you work out the difference between them.
Worked Examples
QUESTION 1
What is the length of the shaded bar in the image shown?
QUESTION 2
I measured my height to be $1.71$1.71 metres with my shoes on. If my shoes are $4$4 cm high, what is my real height without the shoes in metres?
QUESTION 3
How many laps of a $200$200 m track must be completed by a skater competing in the $2$2 km event?