7.1 Units of measure and conversions — Practise with help

1. $60$.
2. $34$.

There are $1000$ metres in one kilometre.

Write $1$ km $=1000$ m, then multiply the number of kilometres by $1000$.

$4.2\times1000=4200$ m.

First convert metres to centimetres. Then square that conversion factor.

Use $1\text{ m}^2=10\,000\text{ cm}^2$.

$1.6\times10\,000=16\,000\text{ cm}^2$.

First find the real distance in centimetres. Then convert centimetres to kilometres.

Multiply the map distance by $50\,000$ and divide by $100\,000$.

$2.4\times50\,000=120\,000$ cm, and $120\,000\div100\,000=1.2$ km.

Add or subtract $180^\circ$ to find the direction back.

Subtract $180^\circ$, because the bearing is greater than $180^\circ$.

$238^\circ-180^\circ=058^\circ$.