Right angle of what a right angle is, namely two straight lines intersecting to form two equal and adjacent angles. The straight lines which form right angles are called perpendicular. Euclid uses right angles in definitions 11 and 12 to define acute angles (those smaller than a right angle) and obtuse angles (those greater than a right angle). Two angles are called complementary if their sum is a right angle. Book 1 Postulate 4 states that all right angles are equal, which allows Euclid to use a right angle as a unit to measure other angles with. Euclid's commentator Proclus gave a
Allied Masonic Degrees Allied Masonic Degrees The Allied Masonic Degrees (AMD) are a series of Masonic degrees conferred by "Councils of the Allied Masonic Degrees". The Allied Masonic Degrees form an appendant order of Freemasonry that exists in some Masonic jurisdictions; its degrees are conferred only by invitation. Councils of the Allied Masonic Degrees exist in Great Britain, the United States, Canada, France and Australia and their members also educate one another by presenting research papers on Freemasonry. The structure is very like that of the craft lodges, with the exception that the offices of Secretary and Treasurer may be combined in some