Bearings & Constructions (DP IB Applications & Interpretation (AI)): Revision Note

Bearings are a way of describing directions using angles

Bearings follow three rules:

• They are measured from the North direction

  • An arrow showing the North line should be included on the diagram

• They are measured clockwise

• The angle is always written in 3 figures

  • If the angle is less than 100° the first digit will be a zero

A question might give you:

• at least three locations

• bearings between some of the locations

• distances between some of the locations

You might have to find a missing distance or bearing

Draw a triangle between the three relevant locations

Label any known distances and angles

• You might have to subtract a bearing from 360° or another angle to find the angle in the triangle

Use the sine and/or cosine rule to find the required answer

You are expected to construct diagrams based on information given

The information might include compass directions, bearings, angles

Look out for the plane the diagram should be drawn in

• It will either be horizontal (something occurring at sea or on the ground)

• Or it will be vertical (Including height)

Work through the statements given in the instructions systematically

You are just required to draw sketches

• However, the more accurate your diagram is the easier it is to work with

Make sure you know your compass directions

• Due east means on a bearing of 090°

  • Draw the line directly to the right

• Due south means on a bearing of 180°

  • Draw the line vertically downwards

• Due west means on a bearing of 270°

  • Draw the line directly to the left

• Due north means on a bearing of 360° (or 000°)

  • Draw the line vertically upwards

Using the above bearings for compass directions will help you to estimate angles for other bearings on your diagram