R I G H T - A N G L E D T R I A N G L E S

As right-angled triangles are a key area of study in trigonometry I felt that it would be rather necessary to make a post purely based on right-angled triangles.

The right-angled triangle is one of the most useful shapes in all of mathematics. It is used in the Pythagoras Theorem and Sine, Cosine and Tangent.

A right-angled triangle is simply a triangle that has a right angle (90°) in it. Every right-angled triangle has a little square in the corner which indicates  that it is in fact a right-angled triangle.

In a right-angled triangle the three sides are given special names. The side opposite the right angle is called the hypotenuse which is always the longest side of the triangle. The other two sides are named in relation to another known angle (or an unknown angle under consideration). 

If this angle is known or under consideration then the side opposite from it is called the opposite side because it is opposite the angle and the side next to it is called the adjacent side because it is adjacent to  the angle.

- k.v.