Bearings for GCSE maths is only a small part of the course, but it is one of the areas we tutors are asked about most. Questions on bearings occur quite regularly in GCSE exams, but the topic is often only covered quickly at school. That’s why revising bearings is so important. There are a few key things to learn and once you know them you will be able to do any GCSE maths bearings questions. Carry on reading through this guide to find everything you need to know.
Bearings – the basics
Bearings provide a way of describing directions. We measure bearings in degrees.
How to measure a bearing
There are three crucial things to remember when measuring a bearing:
- Measure from the north line
- Measure clockwise
- Bearings have three figures (e.g. the bearing for north east is 045°)
Above you can see an example of a bearing measured at 042 degrees and below (in blue) you can see an example of a bearing measured at 330 degrees. All you need to do is use your protractor to measure the angle clockwise from the north line. Then simply write this as a three figure bearing.
Using angle rules to calculate a bearing
As you’ve seen, measuring bearings is relatively straight forward. You will also be asked more difficult bearings questions in GCSE maths. In these questions you will need to use all of the angle facts and geometry you have learned. For example you might need to use parallel line rules, angles on a straight line or angles around a point to calculate bearings, rather than using a protractor to measure a bearing. Take a look at our guide on angle facts if you need to revise these rules. Then check out the example below to see how this works with bearings.
Calculate the bearing of A from B shown on the diagram below.
Start by drawing on the angle you need to find for the bearing of A from B, as shown in blue below.
Now think about which angle rules you can use to help calculate the bearing you need. Given that the north lines are obviously parallel to one another, you can consider all of your parallel line angle rules. Here you can see that the angle marked in green below is co-interior with the 50 degree angle at point A. That means the angle marked in green adds with 50 degrees to make 180 degrees, so the green angle below must be 130 degrees.
That leaves a simple sum to find the bearing (marked in blue on the diagram above) we need. Angles about a point add up to 360 degrees, so we simply do 360 – 130 = 230 degrees. There you have it – a nicely calculated bearing.
It can seem like there’s a lot to remember with bearings, but you just need to know how to measure a bearing with a protractor and how to use your angle rules to calculate bearings where needed. You can find our guide to the main angle rules here to help your revision even further.