Given the lengths of some of the sides or measures of some of the angles of a right triangle, sometimes it is required to solve the right triangle (calculate the lengths of any unknown sides or the measures of any unknown angles of the right triangle).
Usually in any right triangle, the right angle and hypotenuse are labelled first.
The remaining sides are called the legs of the right triangle.
One of the following possibilities will then occur:
- The reference angle (θ) is chosen, and as a consequence one leg is labelled "opposite" and the other leg is labelled "adjacent".
- The legs are chosen to be labelled as "opposite" and "adjacent", and the appropriate angle is labelled as the reference angle (θ).