Protractor 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 a graduated
Tropical geometry Tropical geometry Tropical geometry is a relatively new area in mathematics, which might loosely be described as a piece-wise linear or skeletonized version of algebraic geometry, using the tropical semiring instead of a field. Algebraic varieties can be mapped to a tropical counterpart and since this process still retain some geometric information about the original variety, it can be used to help prove classic results from algebraic geometry, such as Brill–Noether theorem using the tools of tropical geometry. The basic ideas of tropical analysis have been developed independently in the same notations by mathematicians working in various fields (see and