Protractor the UK. Protractor A protractor is a measuring instrument, typically made of transparent plastic or glass, for measuring angles. Most protractors measure angles in degrees (°). Radian-scale protractors measure angles in radians. Most protractors are divided into 180 equal parts. Some precision protractors further divide degrees into arcminutes. They are used for a variety of mechanical and engineering-related applications. One common use is in geometry lessons in schools. Some protractors are simple half-discs. More advanced protractors, such as the bevel protractor, have one or two swinging arms, which can be used to help measure the angle. A bevel protractor is
How many angels can dance on the head of a pin? Suite Part II: Let It Grow", a song from the 1973 Grateful Dead album Wake of the Flood, includes the line "As well to count the angels dancing on a pin." In the comic book "The Crow" by James O'Barr, the main character asks this question to one of his victims before killing them, answering himself, "Depends on the tune". The song "Velodrome" from Minnesota rapper Dessa's 2018 album Chime, references this question in the first verse asking, "Aquinas, call on me/ How many angels on the/ Head of your pin?" How many angels can dance on the head of