Distance and direction

Navigation requires distance and direction. Direction is usually given using three-figure bearings.

Example

Map of an island and a harbour. Scale represents 1cm:1km

A boat leaves harbour to sail around a nearby island. The journey is split into four legs (parts).

The first two legs are given in the table.

BearingDistance
1st leg 063^{o} 5.3km
2nd leg 105^{o} 7.0km
3rd leg
4th leg

To complete the table, first draw a scale diagram.

Step one

Show the first two legs of the journey on the diagram.

5.1km line on 63 degree bearing leads to 7km line on 105 degree bearing. Purple cross at bottom of image.

Step two

Draw the 3rd and 4th legs on the diagram so that the ship travels to the point marked X and then on to the harbour.

5.1km line on 63 degree bearing leads to 7km line on 105 degree bearing. 5.9km line on 238 degree bearing touches purple cross.5.1km line on 63 degree bearing leads to 7km line on 105 degree bearing. 5.9km line on 238 degree bearing touches purple cross. 6.8km line at 293 degree bearing joins up with start.

Part three

Complete the table for these two legs showing the bearings and distance.

BearingDistance
1st leg 063^{o} 5.3km
2nd leg 105^{o} 7.0km
3rd leg 238^{o} 5.9km
4th leg 293^{o} 6.8km