Bearings (SQA National 5 Applications of Mathematics): Revision Note

Bearings

What are bearings?

• Bearings are a way of describing an angle

  • They are commonly used in navigation

• There are three rules which must be followed when using a bearing:

  • They are measured from North

    • North is usually straight up on a scale drawing or map, and should be labelled on the diagram

  • They are measured clockwise

  • The angle should always be written with 3 digits

    • 059° instead of just 59°

How do I measure or draw an angle accurately?

• You need to have a protractor

  • It might go up to 180° or 360°

• Align the centre of the protractor at the point where the two lines meet

• Align 0° with one of the lines

  • You will either use the inner or outer scale

• For measuring:

  • find where the second line meets the protractor

  • read off the number to the nearest degree

• For drawing:

  • put a dot at the correct angle

  • remove the protractor

  • join the dot with the start of the first line

How do I find a bearing between two points?

• Identify where you need to start

  • "The bearing of A from B" means start at B and find the bearing to A

  • "The bearing of B from A" means start at A and find the bearing to B

• Draw a North line at the starting point

• Draw a line between the two points

• Measure the angle between the North line and the line joining the points

  • Measure clockwise from North

• Write the angle using 3 figures 

How do I draw a point on a bearing?

• You might be asked to plot a point that is a given distance from another point and on a given bearing

• STEP 1
  Draw a North line at the point you wish to measure the bearing from

  • If you are given the bearing from A to B draw the North line at A

• STEP 2
  Measure the angle of the bearing given from the North line in the clockwise direction

• STEP 3
  Draw a line and add the point B at the given distance