Suppose you were in the middle of nowhere, and there were no signs or landmarks to help you find your way. Would you know how to find your way home? Someone might tell you via phone or radio to 'walk to your left', or 'turn through and then start walking', but how would they know which way you were pointing in the first place?
One way of describing direction from a point is to use three-figure bearings.
A compass always points north. Bearings are measured from the north line, always in a clockwise direction.
So when someone tells you to walk on a bearing of , you should face north, turn clockwise through and start walking.
An aeroplane takes off from Heathrow airport, as shown in the diagram below.
The angle between the north line and the flight path of the aeroplane is . So we can say that the aeroplane is flying on a bearing of from Heathrow airport.
Click 'Play' to see the direction change in the diagram below. Click 'Pause' to see the bearing.