Triangular and multifaceted corners

There are three rays a, b, c, outgoing from one point and not lying in one plane.



A triangular angle (abc) is a figure composed of three flat angles (ab), (bc) and (ac). These angles are called faces of a triangular angle, and their sides are edges . The common vertex of flat angles is called the vertex of a triangular angle. The concept of a polyhedral angle is also defined.