Since we are fairly familiar with the four main directions - **North, South, East and West** - there is not going to be an issue in identifying
them, as long as we know where **North** is.

The problem, however, arises when we have to express the direction between any two of them - and as a numerical value for accuracy.

By expressing the direction in terms of **bearings** we can overcome a catalogue of practical difficulties in the field of navigation.

Just look at the sky in the following animation near Heathrow, in the United Kingdom; how do aircraft controllers stop these planes from collisions in a saturated sky? It is the role of **three-figure-bearings** that help keep the order in our skies.

This tutorial helps you understand the concept effectively using an *interactive* programme.

A **bearing** is defined as an *angle* measured *clockwise * from the **north direction.**

A bearing is usually expressed in three numbers; therefore, it is called **3-number-bearing.**

**E.g.**

30^{0} is expressed as 030^{0}.

130^{0} is expressed as 130^{0}.

330^{0} is expressed as 330^{0}.

0^{0} 360^{0}

**E.g.1**

The bearing of B from A is 020^{0}. Find the bearing of A from B.

The bearing of A from B = 180 + 20 = 200^{0}.

**E.g.2**

The bearing of B from A is 120^{0}. Find the bearing of A from B.

The bearing of A from B = 360 - 60 = 300^{0}.

**E.g.3**

The bearing of B from A is 220^{0}. Find the bearing of A from B.

The bearing of A from B = 040^{0}.

**E.g.4**

The bearing of B from A is 310^{0}. Find the bearing of A from B.

The bearing of A from B = 180 - 50 = 130^{0}.

**E.g.5**

The following is a map of a part of the United Kingdom. Calculate the bearings of the following cities:

- Bristol from Birmingham
- Birmingham from London
- London from Bristol

- The bearing of Bristol from Birmingham = 180 + 22 = 202
^{0}. - The bearing of Birmingham from London = 360 -45 = 315
^{0}. - The bearing of London from Bristol = 087
^{0}.

These flash cards will make a significant difference when you revise for your forthcoming exams: very informative and neatly presented; they became best sellers for a reason.

**Practice 1:**

By using a *protractor* on the screen, find the following bearings:

- Birmingham from Bristol
- Bristol from London
- London from Birmingham

**Practice 2:**

By using a *protractor* on the screen, find the following bearings:

- Mannar from Kandy
- Kandy from Galle
- Mannar from Galle

Maths is challenging; so is finding the right book. K A Stroud, in this book, cleverly managed to make all the major topics crystal clear with plenty of examples; popularity of the book speak for itself - 7^{th} edition in print.