Sum of angles of a triangle to zero. For a spherical triangle, the sum of the angles is greater than 180° and can be up to 540°. Specifically, the sum of the angles is where "f" is the fraction of the sphere's area which is enclosed by the triangle. Note that spherical geometry does not satisfy several of Euclid's axioms (including the parallel postulate.) Angles between adjacent sides of a triangle are referred to as "interior" angles in Euclidean and other geometries. "Exterior" angles can be also defined, and the Euclidean triangle postulate can be formulated as the exterior angle theorem. One can also consider the
Kings of the Angles such as Wihtlæg, who defeated and killed Amleth, King of the Jutes. Under Wermund the Angles' fortress at Schleswig is said to have been captured by a branch of the Saxons known as the Myrgings, but was retaken by Offa about whom many tales were told (and who is usually referred to as Offa of Angel to distinguish him from his supposed descendent Offa of Mercia). The legends give Offa as bride a daughter of Freawine, governor of Schleswig, and upon becoming king he is said to have secured the Angles' southern border with the Saxons along the River Eider.