Exterior angle theorem sum of angles of a triangle is 180°. If it is known that the sum of the measures of the angles in a triangle is 180°, then the HSEAT is proved as follows: On the other hand, if the HSEAT is taken as a true statement then: Proving that the sum of the measures of the angles of a triangle is 180°. The Euclidean proof of the HSEAT (and simultaneously the result on the sum of the angles of a triangle) starts by constructing the line parallel to side "AB" passing through point "C" and then using the properties of
Facial Angles (Camper) for Philipp von Stosch's "Pierres Antiques Gravées". The facial angles of Moors and Kalmyks was calculated to be 70 degrees, and that of a European 80 degrees. The original report of these lectures in the proceedings of the literature society is listed as one of the 1000 most important texts in the Canon of Dutch Literature. Facial Angles (Camper) Facial Angles refers to the content of two lectures on this subject by the Amsterdam professor of anatomy Petrus Camper on the 1st and 8 August in 1770 to the Amsterdam Drawing Academy called the "Teken-akademie". Camper was a competent artist