Definition:Triangle (Geometry)/Right-Angled

Definition
A right-angled triangle, or right triangle is a triangle in which one of the angles is a right angle.


 * RightTriangle.png

Note that in order to emphasise the nature of the right angle in such a triangle, a small square is usually drawn inside it.

Note the following nomenclature in the context of a right triangle:

Hypotenuse
The opposite side to the right angle is known as the hypotenuse.

Adjacent
For a given non-right angle, the adjacent side which is not the hypotenuse is referred to as the adjacent.