In the case where you have non-right-angled triangles, different methods are required to figure out the area and angles of the triangle.
In the simple case of a right-angled triangle, the area is given by:
If given the lengths of two sides of a triangle and also the angle joining the two sides the sine rule can be applied to determine the area of a triangle. For a triangle ABC with angles a,b & c shown below:
If lengths c and b are known and the angle A is known then the area of the triangle is:
Given three lengths of a triangle, the area of that triangle can be determined. In Heron’s formula a special variable s is introduced. s is the semi-perimeter and is equal to:
The area of the triangle is therefore:
Find the area of the following triangle:
Then, use Heron’s formula
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