Trigonometry can be used to find the length of a side in a triangle. Trigonometry close trigonometryThe study of sides and angles in triangles. can be used to find a missing side in a right-angled ...

How do you calculate that? Choose a line, any line. Since there are six lines, there are six choices. Next, choose a line to be the second side of the triangle.

Revise how to use the sine and cosine rules to find missing angles and sides of triangles as part of National 5 Maths.

The triangles’ sides are these lengths because they obey Pythagoras’s theorem: the square of the longest side is equal to the sum of the squares of the other two sides.