This report aims to research the units for angle measure, including their history, their definitions and the conversion between them. Several common types of units are described in detail, the two most important of which are degree and radian. In addition, how to choose the right unit for angle measure in a specific situation is also discussed.
Angle measure is one of the most basic concepts in mathematics and has been widely used in many mathematical branches, such as geometry, trigonometry, algebra, etc. It’s also used in other fields, such as geography, astronomy and biology. Before using angle measure, it’s necessary to understand the difference of units that measure the size of an angle and the conversion between different types of units. That’s the main purpose of this report.
In geometry, an angle is the figure formed by two rays in a plane. The two rays, called the sides of the angle, share a common endpoint, which are called the vertex of the angle. One ray can coincide with the other by rotating around the vertex, and the minimal required amount of rotation is defined as the size of an angle.