Right Triangle

The right triangle has three sides relative to the angle that defines its shape: the adjacent, opposite and hypotenuse.
Figure 1: Right Triangle

A right triangle is a triangle where one of the three angles is a perpendicular angle. There are three sides of a right triangle: the adjacent, opposite and hypotenuse sides. The sides are labeled relative to the angle of the right triangle denoted with the symbol (theta). Since one of the three angles of the triangle will always be a right angle, only one angle is needed to describe the shape of the right triangle.