Euclidean geometry equal (SAS), or two angles and a side equal (ASA) (Book I, propositions 4, 8, and 26). Triangles with three equal angles (AAA) are similar, but not necessarily congruent. Also, triangles with two equal sides and an adjacent angle are not necessarily equal or congruent. The sum of the angles of a triangle is equal to a straight angle (180 degrees). This causes an equilateral triangle to have three interior angles of 60 degrees. Also, it causes every triangle to have at least two acute angles and up to one obtuse or right angle. The celebrated Pythagorean theorem (book I,
What Is the Third Estate? and operated by independent associations, and therefore society would be self-governed. A comprehensive collection of writings on the topic was released under "Pluralist Theory of the State". Modern equivalent theories building upon the ideas within pluralistic state theory are libertarian socialism and free-market anarchism. An example of the former is guild socialism, one of the founders of which is G. D. H. Cole mentioned above. What Is the Third Estate? What Is the Third Estate? () is a political pamphlet written in January 1789, shortly before the outbreak of the French Revolution, by the French thinker and clergyman Abbé Emmanuel