# Angle Units Converter

## Additional information

Angles are geometric figures formed by two rays or lines that share a common endpoint called the vertex. They are fundamental concepts in geometry and trigonometry and are used to measure the amount of rotation or inclination between two intersecting lines or surfaces.

In the most common system of measurement, degrees (°), radians (rad), or other angular units are used to measure angles. A full circle is divided into 360 degrees, with each degree further divided into minutes (') and seconds ("). Radians, on the other hand, are a unit of angular measure based on the radius of a circle. One full revolution around a circle is equal to 2π radians.

Angles can be classified based on their measure:

- Acute Angle: An angle that measures less than 90 degrees (or less than π/2 radians).
- Right Angle: An angle that measures exactly 90 degrees (or π/2 radians). It forms a square corner.
- Obtuse Angle: An angle that measures greater than 90 degrees but less than 180 degrees (or π radians).
- Straight Angle: An angle that measures exactly 180 degrees (or π radians). It forms a straight line.
- Reflex Angle: An angle that measures greater than 180 degrees but less than 360 degrees (or 2π radians).

Angles can also be classified by their relationship to each other:

- Complementary Angles: Two angles whose measures add up to 90 degrees (or π/2 radians).
- Supplementary Angles: Two angles whose measures add up to 180 degrees (or π radians).
- Vertical Angles: Pairs of opposite angles formed by the intersection of two lines. They are congruent (equal in measure).

**References:**National Institute of Standards and Technology (NIST). “Unit Conversion”. https://www.nist.gov/pml/owm/metric-si/unit-conversion. Wolfram Mathworld. “Angle”. https://mathworld.wolfram.com/Angle.html. Wikipedia. “Angle”. https://en.wikipedia.org/wiki/Angle.