When finding the area of a segment you will often need to find the area of a triangle given two sides and an included angle when the angle is given in degrees or radians. This tutorial shows you how.

## Proof of the formula

## Finding the length of a side of a non right angled triangle

In this tutorial I show you how to find a length of one side of a non-right angled triangle by using the Sine Rule.

You can do this if you are given the opposite angle and another side and the opposite angle.

## Finding an angle of a non right angled triangle

In this tutorial I show you how to find an angle of a non-right angled triangle by using the Sine Rule.

You can do this if you are given the opposite side, another side and the opposite angle.

### The Ambiguous Case

## Finding the length of a side of a non right angled triangle

In this tutorial I show you how to find a length of a side of a non right-angled triangle by using the Cosine Rule.

You can do this if you are given the opposite angle and the two other sides.

## Finding an angle of a non right angled triangle

In this tutorial I show you how to find an angle of a non right-angled triangle using the Cosine Rule.

You can do this if you are given the lengths of all 3 sides.

Here you will find an application of the sine rule and cosine rule in a typical bearings question.