Triangles' trigonometric condition (related to the tangents of the half-angles)

Description

Three positive angles “A”, “B”, and “C”, each of them less than 180°, are the angles of a triangle if and only if holds a specific condition between the tangents of these angles.

Assuming that three arbitrary angles are given, we can calculate if these angles belong to a triangle

Related formulas

Variables

AAngle of the triangle (less than 180°) (degree)
BAngle of the triangle (less than 180°) (degree)
CAngle of the triangle (less than 180°) (degree)